US2620876A - Automatic riveting machine - Google Patents

Description

Dec. 9, 1952 w. E. HARNESS ETAL 2,620,875

AUTOMATIC RIVEZTING MACHINE Filed July 1, 194a 7 Sheets-Sheet 1 INVENTOR. WAYNE E. HARNESS y dorm O. HRUBY JR.

Agent W. E. HARNESS ETAL AUTOMATIC RIVETING MACHINE Dec. 9, 1952 7 Sheets-Sheet 2 Filed July 1, 1946 m: m m W WAYNE E. HARN y dorm O. HRUBY Ill " Aoent Dec. 9, 1952 w. E. HARNESS ETAL 2 7 AUTOMATIC RIVETING MACHINE Filed July 1, 194a 7 sheet -sheet s IN TOM WAYNE HARNESS BY down 0. Hnu

1952 w. E. HARNESS ETAL 2,620,876

AUTOMATIC RIVETING MACHINE Filed July 1, 1946 7 Sheets-Sheet 4 v mmvrons WAYNE E. HARNESS By Joan O. HRUBY JR.

Agent 1952 w. E. HARNESS ETAL 2,620,876

AUTOMATIC RIVETING MACHINE Filed July 1, 1946 7 Sheets-Sheet 5 INVENTORS v WAYNE E. HARNESS BY Joan O. HRUBY JR.

AUTOMATIC RIVETING MACHINE 7 Sheets-Sheet 6 ill! Filed July 1, 1946 M Au- G4 2 L V128 A mmvrozzs WAYNE E. Hmmsss By Jorm 0. Hum JR.

. 5 Agent Dec, 9, 1952 w. E. HARNESS ETAL 2,620,876

AUTOMATIC RIVETING MACHINE Filed July 1, 1946 7 Sheets-Sheet 7 INVENTORJ' WAYNE E. HARNESS By JOHN O. HRUBY JR.

Agent Patented Dec. 9, 1952 UNITED STATE TENT OFFICE 11 Claims. 1

This invention relates to machines useful in the riveting of aircraft components and other objects and assemblies, the invention having particular reference to an improved machine of this class that is fully automatic in operation and low in maintenance cost.

Machines have been developed for performing automatic riveting operations and have found a wide application in many industries. However, the prior machines were designed and constructed in such a manner that they required frequent repair. For example, the life of the punches and dies was very short because the operating linkages allowed misalignment resulting in ultimate breakage. The wearing of the linkages and the breaking of the punches and dies necessitated frequent and prolonged shut-downs of the machines, and involved expensive repair expenditures. The prior machines referred to also lacked adequate provision for adjusting or setting the parts for the dimpling and riveting of material of different thicknesses, and much time was required in making these adjustments.

It is an important object of this invention to provide an automatic riveting machine that will operate at a low maintenance cost. The machine of this invention involves a minimum of mechanical linkages and parts subject to Wear, and accurate alignment of the punch and dies is maintained indefinitely so as to practically eliminate the possibility of breakage. The several operating and shifting mechanisms are actuated directly by fluid pressure units, which in turn, are under control of an electronic system, there being no intermediate mechanism subject to wear and failure.

Another object of the invention is to provide a riveting machine that is operable to automatically perform an entire sequence of operations beginning with the dimpling of the material and ending with the heading-up of a rivet inserted in a punched hole in the material, and that may be selectively set or controlled to perform a single operation or an appropriate sub-sequence of operations. When set or conditioned to perform the full sequence of operations, the machine dimples the material, punches an opening therein, inserts a rivet in the opening and then heads up the rivet, this series of acts being entirely automatic and initiated by simple depression of a pedal, or the like. When less than this complete sequence is desired, the machine may be easily conditioned for successively performing the following individual or dual functions: (a) dimple and punch the work parts, or (b) insert and drive rivets.

The selective control of the machine is effected by simply operating a conveniently located selector switch.

Another object of the invention is to provide a riveting machine of the character referred to which is operable to successively dimple hard and relatively hard alloys and materials. In the 'sequential operations, the sheets of material are first dimpled, and while the dimpled material is held under compression by the'dimpling' dies, the punch is operated to form or punch an opening in the material. The retention of the compression on the material at the dimple during the punching operation assures efiective punching of the work without the development of cracks and without distortion of the material, even in cases where the material is tough and hard.

A further object of the invention is to provide an automatic dimpling machine wherein the depth of the dimple to'be formed in the material or sheets, and the height of the driven rivets may be readily changed or adjusted to condition the machine for the riveting of material of various thicknesses. These adjustments are easily and quickly made by moving electronic contacts with respect to an actuating pneumatic ram, this movement being effected by adjusting knobs conveniently positioned at the front of the machine for this purpose.

A still further object of the invention is to provide an automatic riveting machine incorporating an improved and thoroughly reliable electronic control system which is easily selectively set by the operator to be sequentially operated by movement of the several pneumatic pistons or rams during machine operation.

Other objectives and features of the invention will be readily understood from the following detailed description of a typical preferred form of the invention wherein reference will be made to the accompanying drawings in which:

Figure 1 is a side elevation of a riveting machine incorporating the features of the invention with certain parts broken away to show internal parts in vertical cross section;

Figure 2 is a fragmentary, elevation of the other side of the machine with a portion broken away to illustrate the valves and associated parts, being a view taken substantially as indi a d y line 22 on Fi ur 3;

Figure 3 is a front view of the machine taken as indicated byline ,3 on F gure Figure 4 is an enlarged vertical sectional view of the means for actuating the punch taken as indicated by line 44 on Figure 3;

Figure 5 is an enlarged fragmentary vertical section of the lower anvil assembly and associated parts showing a work piece being dimpled;

Figure 6 is an enlarged fragmentary vertical section of the die and punch assembly showing the punch in the actuated position;

Figure 7 is a view similar to Figure 6 showing a rivet being headed up;

Figure 8 is an enlarged fragmentary front view of the upper active assembly of the machine;

Figure 9 is an enlarged fragmentary vertical section of the rivet guide or feed means;

Figure 10 is a fragmentary elevation view with a portion in cross section taken substantially as indicated by line I0-l0 on Figure 8;

Figure 11 is a transverse sectional view taken as indicated by line I l-I l on Figure 9;

Figure 12 is an enlarged vertical sectional view of the main cylinder taken substantially as indicated by line I2-l'2 on Figure 1;

Figure 13 is a horizontal sectional view taken substantially as indicated by line l3-l3 on Figure 14;

Figure 14 is a vertical sectional view with certain parts in elevation taken substantially as indicated by line l4-I4 on Figure 13;

Figure 15 is an enlarged sectional view of the diaphragm valve;

Figure 16 is a wiring diagram of the electronic circuit means; and,

Figure 17 is a combined wiring diagram and flow diagram of the principal circuits and fluid pressure actuating means of the machine.

The features of the invention are capable of embodiment in machines varying considerably in size, design and application. We will herein describe the preferred form of the machine illustrated in the accompanying drawings, it being understood that the invention is not to be considered as limited to the details of this particular embodiment.

As best illustrated in Figure 1, the machine includes a frame or body ID of generally C shape having a base II, a lower jaw I2, and an upper jaw 13. The forwardly extending jaws are spaced a substantial distance apart to receive the work and the body [0, or at least certain parts thereof, are hollow to contain working parts, etc. An upwardly projecting tubular boss I4 is provided on the lower jaw [2 adjacent its forward end to receive the lower anvil, die and punch assembly to be subsequently described. The active work-engaging elements of the machine are arranged on the forward portions of the jaws l2 and I3 and include a lower die and anvil carrier l5, best shown in Figures 1 and 5. The carrier I5 is guided for vertical movement in the tubular boss 14 and its upper portion is tapered or frusto-conical. A socket I6 is formed in the upper end of the carrier 15 to receive the shank of a die [1, which is removably secured therein by a set screw l8. The active upper end of the die I! has a die cavity or recess 19 to aid in forming the dimples in the work piece and to serve as an anvil or abutment in setting up the rivets. The die I! is tubular, having a central tzertical opening for slidably receiving the punch The lower active assembly further includes a stripper 2| slidable on the exterior of the die 11. The stripper is a tubular part presenting a horizontal upper end face engaging the under side of the work piece W. The lower portion of the die I! is externally flared as shown in Figures 5 and 6, and the stripper 2! is correspond g y shaped so that downward travel of the stripper is limited by the cooperating flared parts. When the stripper is in its lowermost position, its upper surface is flush with the top surface of the die The carrier [5, punch 20 and stripper 2! described above, are each individually operated by fluid pressure actuated mechanisms, preferably in the form of pneumatic cylinder and piston means. The means for operating the carrier 15, that is, for moving the carrier vertically, comprises a cylinder 23, a piston 24 operable in the cylinder and linkage connecting the piston and carrier. In Figure 1 we have shown the cylinder 23 horizontally arranged within the lower jaw 12 so that the rod 25 of the piston extends forwardly for connection with a suitable toggle linkage 26. The linkage is anchored at one end in the jaw l2 and is secured at the other end to the die carrier l5. It will be seen that upon forward movement of the piston 24 the carrier with its die I 1, moves upwardly, and upon rearward movement of the piston the carrier travels downwardly. Air pressure lines 21 extend from the opposite ends of the cylinder 23 to a four-way solenoid valve 28 mounted within the hollow frame jaw and controlled in the manner to be later described.

The means for operating the punch 20 includes a vertical cylinder 28 attached to the forward side of the carrier [5 and a piston 29 which operates in the cylinder and which is provided with a rod 30 extending downwardly through a gland in the lower head of the cylinder, as shown in Figure 4. Spaced lugs 3| on the cylinder head carry a pivoted lever 32. The lever 32 is arranged so that the piston rod 3!! acts downwardly against its forward end and its rearward arm engages a rod 33 guided in an opening 34 in the carrier I5. An intermediate push rod 35 is slidable in the upper portion of the opening 34 and an upper push rod 36 slidably enters the lower end of the tubular die I! to contact the enlarged lower end of the punch 20. The punch 20 is yieldingly supported for retraction, but upon actuation of the piston 29 the punch is positively forced upwardly. A helical spring 31 is engaged under compression between the upper end of the rod 35 and the enlarged lower end of the upper push rod 36. When the work piece W is placed on the die I! preparatory to the dimpling operation or the punching operation, its weight presses the punch 20 downwardly to compress the spring 31. However, when the piston 29 is actuated downwardly the rods 33 and 35 move upwardly to compress the spring 31 until the upper end of the rod 35 engages a reduced stem 38 on the upper push rod 36, whereupon force is positively transmitted to the punch 20 to form an opening in the work piece. Upon the return or upward movement of the piston 29 the rods 33, 35 and 36 are free to return to the normal lower positions. Flexible lines 40 and w deliver air under pressure to the opposite ends of the punch actuating cylinder 28. The lines extend to a solenoid operated valve 209 within the hollow jaw 12. The control for the valve 209 will be subsequently described.

The means for operating the stripper 2| serves to yieldingly urge the stripper upwardly so as to press against the under side of the work piece W around the female die 11. It is contemplated that spring means may be employed for this purpose, but we prefer to use pneumatic cylinder and ram units. Vertical cylinder bores 4! enter the tapering upper portion of the carrier 15 and plungers or rams t2 extend downwardly into the bores as shown in Figure 5. The projecting upper portions of the rams 32' curve upwardly and inwardly and are connectedwith the stripper M at diametrically opposite points by spring clips 43. The air pressure for supplying the bores H is carried by an air pressure line 3 extending from a main supply line and the line t l is branched to communicate with the lower ends of thebores. It is desirable to provide a suitable pressure regulating valve 66 in the line M as shown in Figure ll, which may be set or adjusted to maintain just sufficient pressure in the bores ll to yieldingly urge the stripper 2i upwardly to free the work from the die ii at the completion of the dimpling and/or punching operations.

The upper active assembly carried by the body jaw I3 includes a dimpling shoe 17 and a riveting shoe 48; see Figures 12, 13 and 14. The shoe 4? has an upwardly sloping arm 19 and its lower portion is offset and formed to removably carry a male dimpling die 59. The riveting shoe it has a similar arm 5! and is provided in its lower portion with a vertical opening 52. In the preferred construction, the two shoes ll and are mounted for individual vertical movement and for simultaneous horizontal shifting. The means for carrying the shoes includes shafts 5d slidably received in spaced vertical openings 53 formed in the forward portion of the jaw 53. 59 of the dimpling shoe i! is fixed to the lower end of one shaft 5 3 and the arm 5i or" the rivet ing shoe 48 is secured to the lower end of the other shaft. The shafts are tubular, and their upper end portions are tapered to engage in correspondingly shaped seats 55 in the openings 53 so as to limit upward travel of the shafts. Spring means is provided to urge the shafts 5 to their uppermost portions where the respective shoes 'il and A8 are spaced clear of the work W and to return the parts to these positions after the several operations. These means include bolts or stems 56 extending through the tubular shafts 54 and provided at their upper ends with nuts 5'! for engaging the top surface of the jaw it. Helical compression springs 53 surround the stems 58 within the shafts 54 and are engaged under compression between the lower heads of the stems and internal shoulders 59 formed in the shafts. and 48 are normally held in the upper retracted positions by the springs 58.

Means is provided for shifting the shoes d! and 28 between inactive positions and positions where they are in vertical alignment with the die it and the main ram 8%. This mechanism includes lever arms 69 having sliding spline connections 6i with the shafts 54 so as to allow independent vertical shifting of the shafts while remaining in positive rotation transmitting relation to the shafts. The levers extend from the shafts in parallel relation and their ends are pivotally connected with a common link t2. As best shown in Figure 13, the lever arms @9 and the link 62 are housed in the hollow jaw 3 for free movement therein and piston n echanisrns are supported on the jaw for shifting the link horizontally to move the shoes between their two positions. Horizontal cylinders 83 and as are secured to the opposite sides of the jaw i3 and contain pistons provided with rods 58 which extend into the jaw 3. The shifting link. 62 has a lug 63' extending between the opposing inner ends of the piston rods E8. An air pressure line 63 communicates with the outer end of the cyl- The arm Figure 14 illustrates how the shoes ll A inder 63 and a similar line 690 supplies air under pressure to the outer end of the cylinder 64. The parts are constructed and related so that upon introducing air pressure to the cylinder 63 the riveting shoe 4B is brought to the active position in line with the main ram 58, and upon supplying air pressure to the cylinder 64 the dimpling shoe-41 is moved to its active position in alignment with the ram. It will be observed that shifting of one shoeto the active position simultaneously moves the other shoe to a remote or inactive position.

h Work. mpline nd un n ec an sm further includes a main cylinder and piston unit for actuatingthe above mentioned main ram 68. This unit includes a, vertical cylinder 69 mounted on the forward endof the jaw 13 where its central longitudinal axis is in coaxial relationto the die ll. A piston l0 operates in the cylinder and has a rod H extending downwardly through an opening in the jaw 13. The lower end of the rod H carries a chuck F2 for the ram 63. The lower end ofthe piston actuated ram 63 is engageable with the male dimpling die 50 to drive the same downwardly against the work W when the shoe t! is in the active position, and is adapted to move downwardly through the riveting shoe 48 when the latter is in its active position to drive the rivet as shown in Figure 7. In this connection, it will be observed that the shank of the rivet is upset against the top of the punch 25 and the female die I! so that vertical adjustment of the punch 20 controls the dimensions of the driven rivet. A stop screw 13, shown in Figure 4, is threaded through an opening in the top ofthe cylinder 28-and is engageable by the piston 29 to limit the downward travel of the punch 2t. Thus adjustment of the screw 73 controls the position of the punch 20 for the riveting operations.

Referring again to the main cylinder, it will be seen from an inspection of Figure 12 that a reduced rod or stem 15 extends upwardly from the piston 10 and slidably passes through an opening in the upper head of the cylinder. A disc or washer It is secured on the upper end of the stem ES, and a helical spring 11 is arranged under compression between the cylinder head and washer to return the piston l6 and the punch 68 to the raised position when air pressure in the cylinder is released. The projecting stem (5, spring ll and disc 16 are housed within a suitable hood or cap 18 on the cylinder .68.

t is desirable to incorporate a mechanism for feeding rivets to the riveting shoe t3 and for introducing the individual rivets to the shoe. In the drawings we have shown a simple rivet feed comprising a hopper 30 arranged adjacent the outer end of the body jaw l3 and designed to receive and contain a considerable supply of rivets. The hopper 8i) discharges into a track defined by a, groove 8! in a track member 82 and a slot 83 formed in a plate 85. attached to the track member. The member 82 slopes downwardly toward the shoe 48 and the rivets move by gravity through the track. The groove BI is formed to receive the heads of the rivets, while the rivet shanks extend outwardly through the groove 83 as shown in Figures 9 and 11.

A rivet-selection or gate means is provided at the lower end at the above described track and includes a shjftable gate 85 slidably engegedbetween the lower end of the track member 82 and the upper end of a rivet discharging element 36. The element 86 has a passage 87 for receiving the rivets and for guiding them to the riveting shoe, when the shoe is in the retracted position. The entrance of the passage 81 is shaped so that the rivets swing or tilt to a position where their shanks lead or point downwardly, and the rivets remain in this position as they travel through the passage to the riveting shoe. As best shown in Figure 10, the passage 81 is offset horizontally from the lower end of the track groove 8! and slot 83, and the gate 85 operates to shift the rivets one at a time from the track to the entrance of the passage 81. The selector or gate 85 has a T-shaped notch 88 for receiving an individual rivet and this notch is adapted to register with the track to receive the rivet. Upon shifting of the gate, the notch comes into alignment with the passage 81 to discharge the rivet. In Figure the gate 85 is shown in the receiving position where the notch 88 has just received a rivet from the track.

Cylinder and piston means is provided to shift the gate from this position to the discharging position where the rivet falls from the notch 88 and the passage 81. A cylinder 98 is attached to the track assembly, and the gate 85 has a rod entering the cylinder. A piston 9I on the rod operates in the cylinder 98 and an air pressure line 92 communicates with the outer end of the cylinder. The air line 92 extends to a solenoid operated three-way valve 93 shown in Figure 1'7, and an air line 928 continues from the valve 93 to the valve I14 to be later described. Air under pressure, supplied to the cylinder 98, moves the gate 85 from the receiving position of Figure 10 to the position where it discharges the individual rivet into the passage 87. Spring means is arranged to restore the gate 85 to the receiving position of Figure 10 when pressure is released from the cylinder 98. A yoke or bracket 94 is secured to the track assembly, and a helical spring 95 is engaged under compression between the bracket and an end of the gate 85. It will be seen how the spring 95 automatically restores the gate 85 tothe position shown in Figure 10 when the valve I14 is operated to discharge pressure from the cylinder 98.

In conditioning the machine for each riveting operation a rivet is supplied to the riveting button or shoe 48 by the track and gate means just described. This rivet is retained in the shoe 48 while the shoe is shifted into alignment Y with the main ram 68 and until it is forced into the opening punched in the work piece W. Thus it is necessary to support the rivet in the shoe 48 in position for engagement by the main ram 68 so it will be guided downwardly into the punched opening. The means for temporarily supporting the rivet in the shoe 48 is illustrated in Figure 7 and comprises a pair of diametrically opposite dogs 96. The dogs 98 are shiftably supported in radial slots or openings 91 in the walls of the tubular shoe and are movable toward and away from the vertical axis of the shoe. The opening in the shoe 48 is proportioned to freely receive the head of the rivet and the inner ends of the dogs have sloping surfaces for engaging under the rivet head. The dogs are urged inwardly to normally occupy positions where they will catch and support the rivet introduced into the upper end of the shoe. Leaf springs 98 on the exterior of the shoe 48 urge the dogs 98 to the active positions indicated in broken lines in Figure 7. The full lines of Figure 7 show the dogs in their outermost positions with the ram 68 engaged in the shoe opening 52, Upon retraction of the ram from the shoe 48 the springurged dogs 96 return to the positions where they are operable to stop and support the next rivet. It will be observed in Figure 7 that the lower end of .the main ram 68 is reduced in diameter to enter the shoe opening 52 and to have a downwardly facing shoulder 99 for contacting the shoe 48. The shoulder 99, acting on the upper end of the shoe 48, moves the shoe downwardly against the work piece W to the position illustrated in Figure 7.

As will be subsequently described, the work piece work W is securely clamped between the male and female dimpling dies I7 and 58 during the punching operation, and the punch 28 is operated upwardly to punch the opening in the dimpled material. Figure 5 shows the parts in position for the pimching operation, and Figure 6 illustrates the punch in its fully operated position. It will be seen that the upper or male die 58 has a central opening I88 for receiving the punch 28 as it moves upwardly through the work part. The punch 28 displaces slugs S of material upwardly through the opening I88 as it forms the opening in the work piece. Means is provided for clearing the slugs from the opening I88 of the die 58. A lateral opening I8I joins the upper end of the opening I88 and an air pressure nozzle I92 is threaded in an aligned opening in the die 58 to discharge a stream of air across the top of the opening I88 and through the opening I8I. As shown in Figure 6, the slugs S on the top of the punch 29 are carried to a position adjacent the nozzle I82 so that the jet of air blows the slugs out through the opening I8I. An air line 183 leads from a four-way diaphragm valvc I04, to be subsequently described, to the nozzle I82. The line I83, or at least the portion of the line adjacent the shoe 58, is flexible so that it does not interfere with free movement of the shoe.

The elements thus far described are fluid pressure operated in the embodiment illustrated being pneumatically actuated, and the invention provides a versatile, dependable electronic control system for obtaining automatic, sequential and independent actuation of the several mechanisms to perform the dimpling, punching and riveting functions. In Figure 16 we have illustrated what may be termed the internal electronic circuit which comprises an initiating stage A, a plurality of intermediate stages B, C, D, E, F and G, and a reset stage H. The initiating stage A includes a thyratron or gas filled triode tube I85 having a current limiting resistor I86 connected in its grid circuit and a surge protection condenser I8! tapped into the grid lead. A relay or switch means is provided to initiate firing of the tube I85. As shown in Figure 17, this means comprises a relay I88 which is initially or normally open, and a condenser I 89 is connected with one pole of the relay. A lead 9 extends from another pole or contact of relay I88 to terminal A The grid of tube I85 is connected with the lead 9. A D. C. power source III is provided to give bias for the control of the grids of the tubes in the various electronic stages. A common line IID extends from the negative side of the bias source I II to a limiting resistor 8 of high enough resistance to allow condenser I89 to temporarily bring the bias on tube I 85 to a voltage low enough to render tube I85 conductive. Resistor 8 is connected between lines 9 and I I8. When the relay I88 is in the open condition, its associated condenser I89 has a zero charge. Upon operation of the relay I 88 which may be effected by depressing a foot pedal I54 (see Figure 17), the zero charge 9 is impressed on the grid of tube IE5, firing the tube, or in other words, rendering the tube conductive.

The initiating'stage A further includes a relay I I3 having three posts or terminals A A and A for connecting with external circuits, which will be later described. One side of the relay winding is tied into the plate of the tube I 35 by line I I9 and a lead I28 connects the other side of the winding with a suitable power supply I 22 through a network IZSi-IE-I to be later described. One blade or contactor I Id of the relay is initially in a position where it electrically connects terminals A and A and upon energization of the relay, this connection is opened and the 'contactor connects terminals A and A The second movable blade or contactor I I of the relay initially makes electrical connection between a terminal I It'tied into the bias source III through lead He and a lead iI'I. Upon energization of relay I I3, contactor SIS breaks this connection and moves to a position where it connects the lead I II with the terminal of a potentiometer lit. The other terminal of the potentiometer is connected with a grounded timing switch I2I. A voltage limiting resistor I23 is interposed in the power line I26 and a peak charge condenser I24 is tapped off the line 52$ to ground at a point between the resistor and the relay H3. The function of the above described elements will later become apparent The initiating stage A is associated with the intermediate stage B to control actuation thereof. Referring again to Figure 16, intermediate stage B comprises a thyratron tube I25 having a lead I25 extending from its grid and provided with a current limitin resistor I21. The lead I26 extends to a terminal B which has connection with an'extern'al circuit to be later described. The relay I28 of the first intermediate stage B has one terminal of its actuating winding connected with the plate of tube I25 and a lead I 28 connects the other terminal of the winding with the power line I29. A voltage limiting resistor I BI is interposed in the line I29 and a peak charge condenser I 32 is connected to the line at a point between the relay coil and the resistor. The relay of stage B is similar to the relay of the initiating stage A and includes a blade or contactor I33 initially in a position where it connects terminals B and B Upon energization of relay I28, the contactor I 33 breaks this connection and electrically connects terminals B and B The second blade I36 of the relay initially makes connection between a terminal I34 in the bias line I It and a line I35 extending to the timing resistor condenser circuit of the next intermediate stage 0. Upon energization of relay I28, the blade I36 breaks this connection and completes a circuit between said line I35 and a terminal of a timing potentiometer I31. A switch I33 is connected between the other terminal of potentiometer I37 and ground. The above described lead III extending from blade H5 of relay II 3 connects with the grid lead of tube I25 and with a timing condenser I69. A maximum timing resistor MI is associated with condenser I48. Condenser !db and resistor It! are operable to timeout the tube I25 as will be described below.

New referring again to initiating stage A, it will be assumed that initiating relay I538 is operated to fire tube IE5 as described above. In the event switch I 2i is closed at this time, firing of tube I 85 energizes relay II3 to complete a circuit through terminals A and A andto complete a circuit from condenser Mai through potentiometer us to 10 ground. Completion of the circuit through the potentiometer discharges the charge in condenser M0 to the extent that tube I25 of the intermediate stage B becomes conductive to energize relay I28 of stage B. This timing-out of tube I25 is controlled primarily by potentiometer I I8, resistor l' ii being of an extremely high value with respect to the potentiometer. Thus it will be seen that if switch I 2i is closed when relay I I 3 is energized, timing-out of the tube I25 is determined by the setting of potentiometer II 8. In the event switch I2! is open when tube I of initiating stage A becomes conductive, energization of relay II3 brings the maximum timing circuit comprising condenser H36 and resistor I II into play. Because of the value of resistor IGI, the tube I25 of stage B is held nonconductive for a substantial period for the purpose to be later described.

Intermediate stages 0, D, E, F and G may be identical with intermediate stage B just described, and are related one to the other in the manner in which stage A is related to stage B. Accordingly, in order to'simplify the disclosure, the details of stages C, D, E, F and Cr are omitted from the drawings, andin referring to theelements of thesestages, reference numerals will be used corresponding to the reference numerals applied to corresponding elements of stage B withtl'ie' respective exponents C, D, E, F and G added thereto. However, in the case of the external terminals of stages C, D, E, F and G, th'ese'are designated C C C and C D D D andD and so on, as clearly appears in Figure 17.

When lead I28 is energized before the-machine is operated, condensers I24, I32 and I32 to I32 inclusive are charged to the maximum peak voltage of power supply I22. When tube I05 becomes conductive, the peak charge of condenser I 24 is available for quick energization of relay I I 3. Upon energization of relay II 3, the'charge is partially drained oil from the condenser and resistor I23 becomes part of a dividing network lowering the continuous voltage applied to relay I I 5. This allows the relay to remain energized without overheating. The peak voltage networks I3I, ISI to ISI and I32, I32 to I32 of the severalintermediate stages 13 to G inclusive, function in a similar manner when their respective tubes I25 and I25 to IZE inclusive become conductive.

The several stages A to G inclusive are interconnected in the following manner, as shown in Figure 17. A conductor or lead 2I3 extends from a power supply line I92 to terminal G of stage G. Relay I 28 normally connects terminal G with terminal G An interconnecting line 2M connects terminal G with terminal F of stage F. Relay I28 normally connects terminals F and F and an interconnecting line 2I5 joins terminals F and E Relay I23 normally connects terminals E and E and an interconnecting line 2H3 joins terminals E and D Relay IZB normally connects terminals D and D anda line 2H joins terminals D and C Relay I23n0rmally connects C and C and a line 2i 8 joins terminals C and B Relay I28 initially connects terminals E and B and a connecting-line 2H3 joins terminals B and A Terminal A is connected with terminal A by the contactor H4 of relay '5 it when the same is in itsd'e-energized condition. -t will be seen that this arrangement interlocks'the several stages in such a manner that delivery of current to their respective terminals 2' and d depends upon-the position of their relays.

' The internal electronic circuit further includes a reset stage H for breaking the full wave D. C. voltage from the power source I22 to the tubes 295, I25, I25 I I25 I25 and I25 and for discharging the several condensers I24, I32 I32 I32 I32 and I32 to render the related tubes of stages A to G inclusive, non-conductive, thereby restoring these stages to their normal or initial condition. Reset stage H includes a gas-filled triode 0r thyratron tube I42 having a current resistor I21 in the portion of its grid circuit extending to its terminal H The lead I35 from the relay blade I 36 of stage G taps into the grid lead, and extends to a timing condenser I40 A maximum timing resister I4I is associated with the ground condenser I40 It will be seen from an inspection of Figure 16 that tube I42 of reset stage H becomes conductive in the same manner as the tubes I25 of the intermediate stages, either through the timing-out action of potentiometer I31 or resistor I4I The reset stage H further includes a relay I43 connected between the plate lead I44 of tube I42 and a lead I45 extending from the half-wave portion of power source I22. A current-limiting resistor I46 is interposed in lead I45 and a smoothing condenser I41 is connected in the lead across the winding of relay I43. The relay has a contactor or blade I48 connected with a terminal of above described line I20 and operable between a position where it engages a grounded pole I49 and a pole connected with a line I50 carrying full wave voltage from the power supply I 22. When the relay I43 is in the de-energized condition, the blade I48 is in engagement with the terminal of line I50.

When the tube I42 is made conductive as described above, the relay I43 breaks the full wave D. C. voltage circuit to the tubes I05, I25 and I25 to I25 inclusive. Energizing of relay I43 also brings the blade I48 into engagement with the grounded post I49 to discharge condensers I24, I32 and I32 to I32 inclusive, rendering the tubes of several stages A to G inclusive, nonconductive and allowing their related relays II3, I28 and I28 to I28 inclusive, to restor to their initial positions. Restoration of relay I 28 applies full negative voltage from source I I I to tube I42 of stage H, making the tube nonconductive. This restores relay I43 and completes the full sequence cycle. It will be observed that the internal electronic circuit is automatic upon closing of the switch I54 to carry out a full sequence of operations throughout the several stages A to H inclusive. A case I56 mounted on a side of the body I0 contains the above described electronic stages A to H inclusive, and the power supply means I22.

The external circuits of the system include a master switch I52 for controlling delivery of current to the power supply I22. An indicator lamp I53 may be exhausted with the power supply to indicate the position of the master switch. The above described initiating relay I08 is connected in series with a pair of pedal operated switches I54 so related that depression of a common pedal closes both switches. A safety switch I55 is also connected in series with the foot switch I54 and relay I08, and is operated to allow heating of the tubes of stages A to H inclusive. The above described solenoid valve 28 for controlling delivery of air under pressure to cylinder 23 has one lead 2I0 extending to the power supply and has another lead I58 extending to a switch I59 connected with a second power lead I60. The switch I59 is a double pole switch and is also connected in series with the foot switch I54, safety switch I55 and relay I08. Thus in order to condition the machine for operation, the switch I59 must be closed to actuate the piston 24, which brings the anvil or carrier I5 to its raised operative position.

With the switches I55 and I59 closed, the foot switch I54 is closed to initiate operation of the machine. Closing of the switch I54 energizes relay I08, which applies D. C. current to all stages A to H inclusive, of the internal electronic circuit, and applies a zero charge of the condenser I01 to the grid of the tube I05 of initiating stage A. As above described, this fires tube I05 and actuates relay II 3 of stage A. A lead I10 extends from post A of stage A to a relay I1I which has a pole and blade I12 interposed in a power line I13 extending to a solenoid operated four-way valve I14. Upon firing of tube I05 of stage A, relay IN is energized and solenoid valve I14 is reversed or operated. Solenoid valve I14 is operable to connect an air pressure supply manifold I15 with the pipe 690 leading to the right-hand shifting cylinder 64 so that the piston therein is operated to shift the dimpling shoe 41 into alignment with the main ram 68. This actuation of solenoid valve I14 also supplies air under pressure from manifold I15 to lines 920 and 92 leading to the above described rivet gate or selector cylinder 90. It will be seen that energization of stage A results in shifting of the dimpling shoe 41 into alignment with the main ram and delivery of a rivet into passage 81 of the rivet feed means.

A selector switch I62 is provided to either condition the internal electronic circuit for the full sequence of operations of the machine or for punching only, or for riveting only as desired. The switch I62 is interposed between the posts or terminals B C and D of stages B, C and D, and certain external contacts embodied in the machine. A line I63 extends from post B to a post of the switch I62 and the related switch blade I64 is engageable therewith to complete a circuit through a line I 65 extending to an external contact I66. As illustrated in Figure 13, contact I66 is in the nature of a post extending through a tubular insulating screw 300 which in turn is threaded through an opening in the head of the left hand shift cylinder 63. The inner end of the contact I66 is engageable by piston 65.

The next phase of the operation is effected by engagement of the left-hand shift piston 65 with the above described contact I66. Contact I66 is connected with terminal B of the first intermediate stage through the medium of line I65 and selector switch blade I64 so that engagement of the piston with the contact I66 grounds this circuit and thus renders the tube I25 conductive. The timing switch I2I of stage B is open at this time, and the maximum timing circuit I40I4I allows ample time for the grounding of circuit I64 and I65 as just described. The conductive tube I25 energizes relay I 28 and contactor I 33 comes into engagement with terminal 13 This energizes a relay I11 having a contactor I18 interposed in a lead I19 extending from a solenoid actuated four-way valve I to a common A. C. power lead I91. Valve I 80 controls communication between the air pressure manifold I15 and a line I8I, and communication between the line I8I and the atmosphere. Line I8I extends to one end of a diaphragm valve I04 illustrated in detail in Figure 5.

Diaphragm valve I04 includes a tubular body I82 provided at its ends with caps or heads I63.

A partial partition in the body carries a tubular seat member I99 and defines two end chambers I95 and I99. The memberIB I extends into these chambers and its end surfaces constitute annular seats which oppose the heads I93. Flexible diaphragms I97 and I99 are secured against the ends of the body I92 to extend acrossthe chambers I85 and I89. The diaphragms are movable into and out of engagement with the adjacent ends of the seat member I84. An exhaust port I89 communicates with the inner portion of chamber I89 and an air pressure supply line I99, leading from manifold I75, communicates with the inner portion of chamber I95. It will be observed that the effective areas of the diaphragms I87 and I88 exposed to pressure introduced into the outer ends of the chambers I95 and I85, are considerably larger than the areas of the diaphragms exposed at the interior of the seat member I99 and the areas exposed around the seat member. Accordingly, pressure admitted to the outer end of a chamber holds the related diaphragm I97 or I98 engaged with the seat member I99 and resists comparable pressure within the seat member I89 or within the annular space surrounding the seat member. Release of pressure from an outer end of a chamber I85 or I 98 allows the related diaphragm to open away from the seat member. A pipe I99= communicates with the interior of the seat member I84 and extends to the upper end of the main cylinder 69.

When relay I77 is energized to reverse the solenoid actuated valve I89, pressure is relieved from line I8I and the outer end of chamber I85. This allows diaphragm I87 to move to the open position so that air under pressure pipe I99 flows through pipe I99 to the upper end of the main cylinder 99. Substantially simultaneously with this action, air under pressure is supplied to the outer end of chamber I96 to close the diaphragm I98 against seat member I89 and thus close off the exhaust I89.

The means for effecting reversal of diaphragm I99 includes a relay I9I energized upon actuation of relay I77. A lead I92 extends from the coil of relay I9I to the power supply I22 and the above described relay I77 has a contactor and pole combination interposed in lead I92. Thus, upon energization of relay I77, relay I9I is also energized. Relay I9I controls a four-way solenoid actuated valve I93. Relay I9I has a blade and pole I95 interposed in a lead I96 extending from the supply line I97 to the solenoid of valve I93 so that energization of the relay operates or reverses the valve. Valve I93 governs a pipe I94 leading to the outer end of diaphragm valve chamber I89 to either connect the same with air pressure supply manifold I75 or the atmosphere. Energization of relay I9I reverses valve I93 so that air under pressure is supplied to pipe I94 and chamber I99. It will be seen that upon firing of tube I25, valves I89 and I93 are reversed to reverse the diaphragm valve I94 so that air under pressure is supplied to the upper end of the main cylinder 99 to actuate the ram 68 downwardly.

In accordance with the invention, means is provided for limiting the initial downward stroke of the main ram 98 so as to control the depth of the dimple formed in the work W, and the strokelimiting means serves to initiate operation of the intermediate electronic stage C. A dimple depth contact is provided in the lower portion of the main cylinder 59 to be engaged by ,thepiston 79 as it descends. A plate I98 of dielectric matepower supply I22.

rial is secured to the under side of cylinder69 and carries a bushing I99. A tubular thumb screw 299 is threaded upwardly through the 'bushing and passes freely through an opening in the cylinder wall to enter the cylinder. An elongate contact stem 29I is slidable in the thumb screw 299 and has a. head at its lower end for contacting the under side of the thumb screw knob. A spring 292 is engaged under compression between the screw 299 and a head on the upper end'of the stem 29I to urge the stem upwardly. It will be seen that rotation of the screw 299 vertically positions or adjusts the contact stem 29I. The knob of the screw 299 is conveniently accessible at the front of the machine so that the operator may readily vary or regulate the depth of the dimples to be formed.

A lead or conductor 293 is electrically connected with the contact stem 29I through the medium of the bushing I99 and screw 299, and extends to the post C of the intermediate'electronic stage C. When the main piston 79 moves into engagement with the contact stem 29I, the grid circuit of stage C is grounded to make the tube I25 conductive. This in turn energizes relay I28 to bring the blade I33 into contact with post C A line 295 extends from terminal C to a relay 299, a circuit for energizing relay 295 being completed through lead 295, contactor I93 and post C Relay 299 includes a post and contactor 297 interposed in a lead 298 extending from power line I97 to oneside of the solenoid of a four-way valve 299. The other side of this solenoid is tapped into line 2I9 extending to the Valve 299 governs the above mentioned pipes 99 and 49 which lead to the upper and lower ends respectively of the punch operating cylinder 29. When the solenoid of valve 299 is in the normal de-energized condition, the valve connects the pipe 99 with an air pressure supply line 2I2 so that the piston 29 is held in the upper position. Upon reversal of the valve 299, effected by operation of relay 299, pipe 49 is put into communication with pressure line 2I2 and pipe 99 is allowed to exhaust to atmosphere. This actuates piston 29 downwardly and the punch 29 is forced upwardly to form an opening in the dimpled work piece. It is to be observed that air pressure is maintained in the main cylinder 99 at this time and the work W-is tightly clamped between the dies I7 and 59 as it is punched. This assures the production of a true clean opening in the work with a minimum of distortion.

As described above, slugs S of the sheets or work pieces W are pushed upwardly through the opening of die 59 when the punch is operated. The invention provides for the delivery of air under pressure to the nozzle I92 to blow these slugs free. The above mentioned line or pipe supplying the air nozzle I 92 is in communication with the pipe I94 which extends between solenoid operated valve I93 and diaphragm valve I99. When the valve I99 is reversed te-close off the exhaust I99 of the diaphragm valve as previously described, air under pressure is also supplied to the nozzle I92 through line I93. A stream of air discharges from the nozzle I92 at a substantial velocity so long the solenoid of valve 699 remains energized. Accordingly, the slugs S formed during the punching operation are blown clear through the opening IEiI by the air blast as the punch approaches the upper end'of its stroke.

At the instant the blade or contactor I33 of stage C is operated toward post the circuit to the coil of relay of I1! is opened to de-energize the relay Ill. The current to relay IT! is carried by relay I28, line 2I'I, relay I28 and a line 500 extending from post 13' to the winding of the relay. When relay I28 is energized as just described, this circuit is broken between terminals C and C De-energization of relay III causes reversal of solenoid operated valve I80, which in turn seals off both ends of the diaphragm valve I04 to lock the ram 66 in its down or dimpling position. When blade I33 moves into engagement with terminal C a circuit is completed to the winding of relay 206 through lead 205. Energization of relay 203 energizes solenoid actuated valve 209 to supply air under pressure to cylinder 28 through line 40. This actuates the punch to form an opening in the work pieces W.

The above described actuation of the punch 20 causes operation of electronic stage D, which in turn ole-energizes relays I9I and 205. As shown in Figure 4, a rod 22I is attached to the cylinder 28 of the punch operatin mechanism and a sleeve 222 is slidable on the rod. The sleeve is yieldingly urged upwardly by a spring 223. A projecting arm on the sleeve 222 carries an insulated contact 224 in position to be engaged by the lever 32 when the punch 20 reaches the upper end of its movement. A conductor 225 extends from contact 224 to the terminal D of stage D. Upon engagement of the lever 32 with contact 224, the grid circuit of tube I is grounded to discharge condenser I and the tube is made conductive. This energizes relay I28 to break the connection between terminals D and D This in turn de-energizes relays I9I and 206. Deenergization of relays I9I and 206 results in reversal of the solenoid operated valves I93 and 209 so that the spring TI is free to restore the piston I0 to its raised position and to move the ram upwardly out of engagement with the die 50. Valve 209 is also reversed to cause the punch 20 to descend. Relay III remains energized at this time to hold valve I14 in the actuated position so that the dimpling die remains in line with the ram 68. Relay III is locked in by a lead 226, tapped into the interconnecting line 2I6 and extending to a second contactor 221 of the relay, the contactor being connected with a pole of the relay winding.

The invention provides means whereby restoration of the ram 68 reverses the positions of the dimpling shoe 41 and the riveting shoe 48. A tubular screw 229 is adjustably threaded through a bushing 230 secured in a cli-electric plate on the hood I8 of the main cylinder 69. A contact stem 23I is shiftable in the screw and extends downwardly into the hood. A sprin 232 is engaged between the screw 229 and a head on the lower end of the stem 23I to urge the stem downwardly to its lowermost position. The stem 23I is engaged by the upper end of the rod I5 when the piston I0 returns to its upper position. A conductor or line 233 extends from a post on the bushing 230 to the terminal E of stage E. When the contact stem 23I is engaged by the rod I5, the control grid circuit of stage E is grounded so that tube I25 becomes conductive to energize relay I28 This breaks the connection between terminals E and E and relay III is de-energized so that valve I74 is reversed. Reversal of ant actuation of piston I65 shifts the dimpling shoe 4! to an idle position and moves the riveting button or shoe 48 carrying the previously introduced rivet into alignment with the main ram 68. It will be observed that at this time all external relays are de-energized. The machine is now in condition for the rivetin operation.

Shifting of the riveting shoe 48 to the active position is immediately followed by downward actuation of the main ram 68. The means for accomplishing this includes a contact 234 carried by an insulating screw 235 threaded through an opening in the end of the right-hand shift cylinder 64 so as to be engageable by the piston of that cylinder when it returns to the outer position. A conductor or line 235 is connected to contact 234 and extends to terminal F of stage F. Engagement of the returning piston with contact 234 grounds the control circuit of stage E to render the tube I25 conductive so that relay I28 is energized. In accordance with the invention, this re-energizes or reverses the four-way valves I80 and I93. The means for accomplishing this operation includes a relay 238 having a blade 239 interposed in a line 240 extending from the A. C. power line I91 to one pole of the solenoid operated valve I80. The relay has a second blade 24I in a line 242 extending from the A. C. power line I91 to the line I96 of the solenoid operated valve I93. A conductor 243 extends from the terminal F to stage F to the winding of relay 238 so that energization of relay I28 energizes relay 238 and operates valves I80 and I93. In accordance with the previous description of operation, actuation of the valves I00 and I93 supplies air under pressure to the upper end of the main cylinder 6 9 through the medium of the diaphragm valve I04. This operates the ram 68 downwardly to drive or upset the rivet releasably held in the shoe 48. As shown in Figure 7, the rivet is passed through the punched opening in the work W and its shank is upset against the upper end of the punch 20 and the surface of die The invention provides adjustable means for accurately determining the depth of the rivet and for initiating the next stage of operation. This means includes what we will term a rivet depth contact 244 positioned to be engageable by the main piston 10. A tubular thumb screw 245 is threaded through a bushing 246 in the insulating plate I93 and passes freely into the lower end of the cylinder 89 as best shown in Figure 12. The rivet depth contact 244 is in the nature of an elongate stem shiftable in the screw 245 and provided with heads at its upper and lower ends. A spring 241 is engaged between the upper head of the contact and the screw 245 to urge the contact to its upper position projecting a considerable distance beyond the screw. The contact 244 is at a lower elevation than the dimple depth contact stem 20I and is not engaged during the dimpling stroke of the ram 68. As the piston I0 moves downwardly during the riveting stroke, it engages and depresses the stem 20I, but at this time the circuits associated with the stem are idle. A lead 248 extends from a screw or post on a bushing 246 to the terminal G of electronic stage G. When the piston I0 engages the stem 244, the control grid circuit of tube I25 is grounded and the tube is made conductive. This energizes relay I28 so that its blade I33 moves out of engagement with terminal G As a result, th circuit to terminal F and line 243 is broken to de-energize relay 238. This de-energizes or reverses valve I80 and I93 so that the diaphragm valve I04 operates to cut off theairsupply to the main cylinder 69 and to exhaust .air therefrom. The spring TI restores the piston "It! and ram 58 to their upper positions. It will be observed that the operator may accurately time the operation just described by adjusting the thumb screw 2'55 and thereby regulate or determine the depthof the driven rivet. Upon operation of stage G, the blade I33 of its relay I moves out of engagement with terminal G This clears D. C. current'from all external. relays ll'I, Ill, lei, 2&6 and2238.

The reset stage 1-1 ofthe electronic system .is operated substantially simultaneously with return of the ram 63. Theswitch 138 .of stage G is closed at all times, and upon .energization of relay I28as above described,.timingcircuit is? and MD times-out .the :tube 1 22 of stage When the charge in condenser M9 is reduced to a given degree, the tube I42 becomes conductive to energize relay 1%. Operation of .relay Hi8 breaksthe DCcircuit 120-150 todeeenergize the relays ,IIB, .l28, 428 1130 .t28 inclusive, of the electronic system. lhe contactor of .relay IE8 moves to thepole l'rtllto apply .full negative bias voltage .to the timing condensers. LEA, .149 and l lll to 148 inclusive,.to preventthe tubes of the. several stages :from becoming conductive when voltage .-is .again. applied ;.to the system. Thus the electronic system :is .fully .restored .for the next operation.

The machine .maybe conditioned. to perform given. individual. operations 1 or. a sequence .of; selectedsoperationsshort ;of .a. full sequential cycle. For'examplathe machine may .be .set to :dimple the-work W and punchen. openingthereinzfor the subsequent, reception of axrivet. The above mentioned selectorswitch I 62 is embodied in the external circuit to provide for the performance of selectedoperations orsequence of operations. The selector switch includes the previously mentioned v.blade I66, and additional blades 25,:25I and 2 52. Figural? showsthe selectorswitch :in position fora full sequence cycle of the machine. When desired to only dimple and punch the work .W, the selector switch is moved :to .a position ..where,its blades 250,,2'5I and 252 function as ,describedbelow.

In considering the following description of operation where the machine is employed for dimpling and punching only or for rivetinserting ,and driving ,onlyn the relationship between the yresistances in the control grid circuits of the severalelectronic stagesiis of importance. When the, relay I 28 of. axgiven. stage is .open orin the initial position, .the resistance in the circuit from the condenser I to the line Ilfiis less than the resistance in the circuit from the condenser to the terminal B ,C. ,.D etc., as the case may be. Accordingly, the tubel25 is not made conductive, even thoughthis terminalis grounded by the operation of. some external element of the machine. The relay 528 of aprecedingelectronic stage must be energized or closed tovrender the tube I25 conductive by the grounding of the control grid circuit through the related terminal B C D etc. The resistance I21 adjacent the terminal is of such a value'that upon grounding of the circuit, the related tube I25 is made conductive almost immediately by bleedin 01f the charge in the associated condenser I40.

Thedimpling and punching cycle is initiated in the same manner as the full sequential cycle by closing switches I54, I and I57. This results in operation of electronic stage A to shift dimple die :31 into position between die VI! and ram es. Stage B than operates automatically to supply air under pressure to the upper end of the main cylinder 69 to movethe ram downwardly whereby a dimple is formed in the work W by the dies It and 5.3. The dimple depth contact 235 is engaged by the piston iii] to operate stage C at the completion of the dimpling operation. Actuation of stage C maintainsair pressure in the main cylinder 69 and causesair under pressure'to be supplied to cylinder 28 to actuate the punchlfl. The punch 20 forms an opening in the material held by the dies II and At the completionof the punchingopflration, lever 32 engages contact 224 to energize orifire electronic stageD, which in turneifects the ;return of the ram 68 and punch '20 to their idle positions. Piston it comes into engagement with contact 223i as the rain approaches its uppermost position, and electronic stage E'is operated. This causes the rivet shoe 48 to move into position between the ram 68 and die 17. However, there is no rivet contained in the shoe 48 at this time, and the shoe-is not broughtinto-operation dur t i ns a p nchin s quence Blade 252 of the selector switch lfifl is connected between a lead 25d extending from power line Iii?! and a line 255extend ng to one side of the solenoid operated three-way valve 93. Whenthe selector switch is positioned for dimpling and punching only, the blade252 closes the-cir it just mentioned to operate the valve-93 to a pgsition where the air pressure ;.supply is out -eii from-the rivet gate cylindertl). The rivet gate is thus held in a position where rivets cannot feed into the shoe d8.

Electronic stage F is grou-nded by the selector switch to fire immediately upon'the operation of the electronic stage E, and before the righthand shifting piston engages contact 23 3. Electronic stage G is also fired immediately. Contact 25I of the selector switch is-at this timepositioned to ground a tap 256 from the line 2 38 extending to terminal G Electronic stage G clears .all the external relays of the system andserves'to time-out tube I42 of stageH through circuit I31 lSE -and IM This clears out-the electronic circuits for the succeeding operation.

When the machine is to be used to insert-rivets in previously dimpled andpunched -openingsin the work piece and then to drive the rivets, the selector switch I52 ismoved to the rivetonly position where the blades I 36, 2-5d-and Zircontrol the related circuits. In carrying out the rivet only operation, electronic stage A is operated by closing switch I5d and the other switches in the initiating circuit. This fires'or operates stage Aas above described. lNith selector switch I62 in the rivet only position, the blade I84 engages a terminal to place a resistor 266 in the circuit E55 which connects terminal B and contact I66 at the left-hand shiftcylinder E3. The resistor 26% is of such a value that it delays firing of tube. I25 of stage B:fora sufficient time to allow the rivet to drop into-the shoe 53 from the passagegfi'I. The automatic rivet only cycleissubstantially reduced in-tiine by reason of the fact that stages C and D areimmediately grounded out, as will be described below. This shortening of the-cycle of operation is compensated for'by the delay in the firing of stage B effected by resistorltfl, and the rivet is given ample time to fall into the rivet shoe before the shoe is shifted. Engagement or shift piston 65 with contact I66 results in firing of stage B as described above. This conditions stage C for operation, and blade 250 of the selector switch 162 grounds line 203 so that stage C fires immediately. This conditions stage D, which als fires immediately because blade 25! of the selector switch grounds line 225 leading to the terminal D Thus stages C and D are oper ated in rapid succession and do not depend upon external circuit conditions established by machine operation for their actuation. Stage E of the electronic system operates as above described to cause the rivet shoe 48 carrying the rivet to be shifted into position in line with the main ram 68. Stage F then operates as previously described to actuate the main ram, and the rivet is driven. Electronic stage G operates at the completion of the rivet driving operation by reason of the engagement of piston 16 with the rivet depth contact 244 and actuation of stage G causes the main piston and ram 68 to return to their upper positions. Re-set stage H operates as in the previously described cycles, and the system is restored to the normal condition for the next rivet only sequence. The machine may be repeatedly operated to insert and drive rivets in previously dimpled and punched openings by merely actuating the foot switch I54.

Switches I21, I38 and I38 to I38 inclusive may be omitted if desired. However, they are illustrated in the preferred embodiment of the invention to indicate that the successive stages of the electronic system may be timed out to perform or permit the perfomance of special or selected machine operations as conditions may require.

From the above detailed description it will be seen that we have provided a fully automatic riveting machine that may be employed to carry out a complete sequence of operations, including the dimpling and punching of the work parts, the insertion of the rivets and the driving of the rivets. The machine may also be set to simply dimple and punch the work parts or to insert rivets in previously dimpled and punched openings and then drive the inserted rivets. Thumb screw 200 may be easily adjusted to regulate the depth of the dimples to be formed in the work pieces, and thumb screw 245 may be manipulated to regulate the depth of the rivets. The thumb screws 200 and 245 are located where they are conveniently accessible to the operator, and adjustment of the machine may be accomplished without any delay whatsoever. It is to be observed that the several primary or active elements of the machine are directly operated by cylinder and piston mechanisms, and there are no intervening linkages subject to wear and malfunctioning. The electronic control system assures properly timed sequential operation of the several machine parts and is such that simple setting of the selector switch I62 conditions the machine either for the performance of the full cycle of operations or for dimpling and punching only, or riveting only. The invention provides a trouble-free fully automatic machine capable of rapidly carrying out its several functions.

Having described only a typical form of the invention, We do not wish to be limited to the specific details herein set forth, but wish to reserve to ourselves any variations or modifications that may appear to those skilled in the art and/ or fall within the scope of the following claims.

We claim:

1. In a riveting and dimpling machine, anvil means carrying a die, a ram, a piston for moving the ram toward the die, a shoe shiftable between a retracted position and a position in alignment with said ram and die and capable of movement toward the die, a second die carried by the shoe, cylinder and piston means for shifting the shoe between said positions, means for initiating operation of the first named piston to cause the ram to move said second die against a work piece on the first named die including contact means associated with said cylinder and piston means and closed when the shoe reaches the position in alignment with the ram, and means for terminating movement of the ram toward the anvil to limit the effect of the dies on the work piece comprising an electric control means and contact means for the same operated by said first named piston.

2. In a dimpling machine, anvil means carrying a die, a ram, a first piston for moving the ram toward the die, a shoe shiftable between a retracted position and a position in alignment with said ram and die and capable of movement toward the die, a second die carried by the shoe, means for shifting the shoe between said positions including a cylinder and a second piston operable therein, means for initiating operation of the first piston to cause the ram to move said second die against a work piece on the first named die including contact means associated with said cylinder and said second piston and closed when the shoe reaches the position in alignment with the ram, means for terminating movement of the ram toward the anvil to limit the effect of the dies on the work piece including an electric control system for said first piston and a contact operated by said first piston to govern said system, and manual means for changing the position of the contact to vary the efiect of the dies upon the work piece.

3. In a dimpling machine, anvil means carrying a die, a ram, a first piston for moving the ram toward the die, a shoe shiftable between a retracted position and a position in alignment with said ram and die and capable of movement toward the die, a second die carried by the shoe, cylinder and piston means for shifting the shoe between said positions, means for initiating operation of the first named piston to cause the ram to move said second die against a work piece on the first named die including contact means associated with said cylinder and piston means and closed when the shoe reaches the piston in alignment with the ram, means for terminating movement of the ram toward the anvil to limit the effect of the dies on the work piece including an electric control system, a contact in said system arranged to be engaged by piston to limit movement of said first piston, and an accessible screw threaded member manually operable to alter the position of the contact and thus alter the effect of the dies upon the work piece.

4. In a dimpling machine, a normally stationary die, a die supported for movement toward the stationary die, a ram vertically aligned with the movable die for moving the same toward the stationary die, a cylinder vertically aligned with the ram, a piston operable in the cylinder to actuate the ram, and means for controlling the piston to determine the stroke of the ram and therefore the effect of the dies upon a work piece engaged between them, said means including valve means for controlling the delivery of actuating fluid pressure to the cylinder, an electrical system for operating the valve means and a contact in the system arranged in the cylinder to be engageable 21 by the piston to cause closing the valve when the dies have produced a giveneiiect upon the work p e e- 5'.In a dimpling machine having an anvil means carrying a tubular dimpling die and having a punch movable through'the die, the-combination of a ram movable toward and away from the die, a; dimpling-shoe arranged for movement between-a retracted position and a position in line with the ram and for movement toward and-awayirom-the die,- cylinder and piston means for-moving '-the dimpling shoe into alignment withthe ram, ache in thedimp'ling shoe, cylinder and piston means for moving'the'ram toward the anvil means, means energized by the piston of the-first 'riamed cylinder and piston means for supplying actuating fluid pressure to the cylinder of the second'na'med cylinder and. piston means to actuate theram so tha't said dies form a dimple ina wo'rklpiec'e, means'controlled by the piston of the ram actuating means for operating the punch to form an opening in the work piece, and means controlled by the punch actuating means for moving the ram away from the anvil.

6. In a machine of the class described for dimpling and punching a work piece, a stationary die, a shiftable die, means for shifting the second die into alignment with the first die, a ram for moving the second die toward the first die to form a dimple in the work piece, a punch movable through the first die to form an opening in the dimple, and an electronic control for producing sequential operation of the die shifting means, ram and punch on the order named, said control including contact means rendered active upon said shifting of the second die, a first electronic stage operated by said contact means to cause actuation of the ram, contact means rendered active upon full actuation of the ram, and a second electronic stage operated when the second contact means becomes active to cause actuation of the punch.

7. In a machine of the class described for dimpling and punching a work piece, a stationary die, a shiftabl-e die, means for shifting the second die into alignment with the first die, a ram for moving the second die toward the first die to form a depression in the work piece, a punch movable through the first die to form an opening in the depression, and an electronic control for producing sequential operation of the die shifting means, ram and punch in the order named, said control including a first electronic stage manually initiated to cause actuation of the die shifting means, a second electronic stage conditioned for operation upon operation of the first stage and operable to cause operation of the ram, contact means operated upon said shifting of the second die to cause operation of the second stage, a third electronic stage conditioned for operation by said second stage and operable to cause actuation of the punch, and contact means operated upon actuation of the ram to cause operation of said third stage.

8. In a machine of the class described for dimpling and punching a work piece, a stationary die, a shiftable die, means for shifting the second die into alignment with the first die, a ram for moving the second die toward the first die to form a dimple in the work piece, a punch movable through the first die to form an opening in the dimple, and an electronic control for producing sequential operation of the die shifting means, ram and punch in the order named, said control including a first electronic stage manually ini- 22 tiate'd to cause actuation of the die "shifting means, a' s'econd electronic stage conditioned for operation upon operation of the first stage and operable to cause operation of the ram, contact means operated upon said shifting of the "second die to cause operation-of the second stage, a third electronic-stage conditioned for operation by said second stage and operable to cause actuation of the punch, and 'contact means ope'rated upon actuation'of the 'ram' to cause operation of said third stage, each of said stages including a relay controlling the element which that stage operates and also operable to condition the succeeding stage, a tube for energizing said relay and having a control grid circuit grounded by one of said contact means to render the tube conductive to energizethe-relay.

9. In a machine having a stationary die, a shiftable die and a ram for moving the shiftable die against a work piece-on the stationary die the combination of means for shifting-the die into alignment with the ram, me'ans for operating the ram, and a control system comprising a first electronic stage including a re lay for operating the die shifting means, a tube for energizing the relay and having a control grid circuit, and manually operable means for controlling said circuit to render the tube conductive so as to operate the relay, and a second sta e comprising a relay for causing actuation of the ram operating means, a tube having a control grid circuit conditioned by operation of the relay of the first stage and contact means operated upon shifting of the shiftable die to the position where it is aligned with the ram for grounding the grid to render the tube conductive.

10. In a machine having a stationary die, a shiftable die and a ram for moving the shiftable die against a work piece on the stationary die the combination of; means for shifting the die into alignment with the ram, means for operating the ram, and a control system comprising a first electronic stage including a relay for operating the die shifting means, a tube for energizing the relay and having a control grid circuit, and manually operable means for controlling said circuit to render the tube conductive so as to operate the relay, and a second stage comprising a relay for causing actuation of the ram operating means, a tube havin a control grid circuit conditioned by operation of the relay of the first stage, said grid circuit including contact means actuated by said means for shifting the die to ground the grid circuit to render the tube conductive upon shifting of the shiftable die to the position where it is aligned with the ram.

11. In a machine having a stationary die, a shiftable die and a ram for moving the shiftable die against a work piece on the stationary die, the combination of; means for shifting the die into alignment with the ram, means for operating the ram, and a control system comprising a first electronic stage including a relay for operating the die shifting means, a tube adapted to be made conductive to energize the relay, a grid circuit for the tube normally imposing a negative bias to hold the tube nonconductive, manually operated means for controlling said grid circuit to render the tube conductive to produce actuation of the die shifting means, and a second stage including a relay for causing actuation of the ram operating means, a tube operable when conductive to energize the second stage re- 23 lay, a control grid circuit for the second stage normally connected with a bias source by the first stage relay and disconnected therefrom upon operation of the first stage relay, a condenser in the second stage grid circuit maintaining a sufficient bias charge to hold the second stage tube non-conductive, and contact means for grounding the second stage grid circuit upon shifting of the shiftable die into alignment with the ram to bleed said charge from the condenser to render the second stage tube conductive.

WAYNE E. HARNESS- JOHN O. HRU'BY, JR.

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

UNITED STATES PATENTS Number Name Date 2,063,691 Marchant Dec. 8, 1936 2,069,042 Marchant Jan. 26, 1937 Number Name Date Oeckl et a1. Oct. 1, 1940 Weingold Feb. 4, 1941 Hagedorn Dec. 22, 194 Ward Dec. 29, 1942 Fluke Jan. 5, 1943 Hill Apr. 6, 1943 Merriman Sept. 7, 1943 Ward Feb. 8, 1944 Mayer et a1 Aug. 22, 1944 Rechton et a1 Mar. 27, 1945 Speller May 8, 1945 Grifiin Mar. 16, 1948 Christensen Mar. 30, 1948 Johndrew Dec. 14, 1948 Fischer Jan. 4, 1949 OTHER REFERENCES The article on pages 323 and 324 of the Review 20 of Scientific Instruments, November 1939, vol

ume 10.

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