US2463669A - Automatic chain pin riveting machine - Google Patents

Description

March 8, 1949. WRIGHT 2,463,669

AUTOMATIC CHAIN PIN RIVETING MACHINE Filed Sept. 5, 1947 v 4 Sheets-Sheet 1 IO/ Ei- March 8, 1949. WRIGHT 2,463,669

AUTOMATIC CHAIN PIN RIVETING MACHINE Filed Sept. 5, 1947 I 4 Sheets-Sheet 2 izz-e I ,[NVENTOE FRED J. WEIGHT) ym/m ATT'Y March 8, 1949. wRlGHT 2,463,669

I AUTOMATIC CHAIN PIN RIVETING MACHINE Filed Sept. 5, 1947 4 Shets-Sheet s.

Fig-3 f/vve-NTo/e FRED J. WEIGHT,

March 8, 1949. J WRIGHT Q I 2,463,669

AUTOMATIC CHAIN PIN RIVETING MACHINE Filed Sept. 5, 1947 4 Sheets-Sheet 4 [/vvE/v7o/e; FRED J. WEIGHT;

HTT X l ular openings Patented Mar. 8, 1949 AUTOMATIC CHAIN PIN RIVETING MACHINE Fred J. Wright, Columbus, Ohio, assignor to '1 he Jeffrey Manufacturing Company, a corporation of Ohio Application September 5, 1947, Serial No. 772,319

10 Claims.

This invention relates to an automatic chain pin riveting machine, and an object of the invention is to provide an improved machine of this type in which the pin to be riveted is heated locally while in the chain, after which it is riveted, the operations preferably being automatically performed.

Another object of the invention is to provide an automatic chain pin riveting machine which will feed chain while the unheaded ends of pivot pins are successively positioned, heated, and headed or riveted; the heating mechanism preferably being a high frequency electrical heater with an inductor head which surrounds the unheaded pin end during the heating operation and which is removed during the heading or riveting operation.

Other objects of the invention will appear hereinafter, the novel features and combinations being set forth in the appended claims.

In the accompanying drawings,

Fig. 1 is a front elevational view of a machine incorporating the features of my invention, with parts broken away and in section;

Fig, 2 is a sectional elevational view of the machine taken substantially at right angles to Fig. 1 and through the approximate center of the machine;

Fig. 3 is a piping diagram of the air and hydraulic circuits employed to perform certain functions of the automatic machine; and

Fig. 4 is a wiring diagram of the machine.

Referring particularly to Figs. 1 and 2 of the drawings, the machine includes a main frame l formed of a pair of parallel spaced-apart upstanding plates 1 I, I l interconnected by a plurality of cross plates and having generally rectangl2 adjacent the top thereof. Mounted in the top of the main frame 10 is a pair of hydraulic rams l3 and M which are in the form of double acting hydraulic cylinder rams, the cylinders of which are rigidly attached to laterally spaced plates l5 and I6, respectively, which are welded or otherwise rigidly attached to the main frame members H and are upstanding and parallel and located on opposite sides of the openings l2. As clearly illustrated in Fig. 1 of the drawings, the rams l3 and M are oppositely positioned so that they face each other and are in alignment on a horizontal axis which extends substantially across the middle of the window provided by the openings l2.

Reciprocating plungers, headers or riveters l1- and I8 of the hydraulic rams l3 and I4, respectively, are in alignment on a horizontal axis and are adapted to be moved toward and from each other to rivet the heated unheaded end of a chain pin, such as the pins I9 of chain 2! the unheaded end of one of which is seen at the left in Fig. l of the drawings. The chain 29, whose pins 19 are to be riveted, is supported upon a horizontal platform 2| rigidly attached to the main frame In and in fact forming a part thereof and extending substantially through the center of the window l2-l2.

Platform 2| has an elongated slot 22 extending rectilinearly down its center (see Fig. 2) below which there is a reciprocating carriage 23 mounted for rectilinear sliding or reciprocating motion in spaced guides 24. The carriage 23 carries one or more pivoted pawls 25 which have their upper ends projecting through the slot 22 and which are mounted for pivotal movement on horizontal axes. The upper ends of the pawls 25 extend between the blocks of the chain 20 and operate in an obvious manner to move the chain 20 forward as the carriage 23 moves forward, since the pawls 25 are held against limited clockwise rotation by stop pins 26. During reverse travel of the carriage 23 the pawls 25 can ratchet over the barrels of the chain 20, thus to engage a succeeding block and move the chain 2!! forward one pitch length for each reciprocation of the carriage 23, thus successively bringing pins it into alignment with the plungers or riveters I! and 18.

It is evident that the horizontal platform 2| is so positioned that the pins I 9 in moving thereover will travel along a horizontal plane which is in alignment with the axis of the plungers or riveters l1 and I 8. It is also evident that the vertical position of the pins 19 is also brought into alignment with said plungers H and i8 by the reciprocating carriage 23 and cooperating pawls 25.

Reciprocation of the carriage 23 to advance the chain 20 and position the pins ll for riveting is effected by a double acting air feed cylinder 27, the cylinder of which is mounted on a platform 28 forming part of the main frame l0, and the piston rod of which is attached by a yoke 29 to the carriage 23.

The pivot pins !9, as they exist in the chain 2!] prior to the riveting operation, preferably have a head on one end, the other end being unheaded. In Fig. 1 of the drawings the pin I9 is shown with a head on the right-hand end, the left-hand end being unheaded. It is preferred that in building up the chain with the unriveted pins, as it travels over platform 2!, the pins l9 as will be successively reversely positioned with respect to the chain 20. That is, each succeeding pin will have its head on the opposite side of the chain and likewise will have its unriveted end on the opposite side of the chain.

The chain 20, as it is fed to the riveting machine, is entirely unheated and a feature of the invention is the provision of mechanism, preferably automatic in character, which will locally heat the projecting unheaded end of each pin 19 to a high temperature, preferably by high frequency electrical induction heating, after which the induction heating apparatus is removed from the unheaded pin end and the rams l3 and [4 simultaneously actuated to move toward each other and through the action of the plunger, header or riveter IT or E8, as the case may be, form a head on the heated pin end, thereby to rivet each pin l9 of chain 20.

Mechanism for heating successive unheaded pin ends which project alternately from opposite sides of the chain 23 and for riveting said heated pinends will now be described. Between the plates ll of the main frame it? is a table 30 which is mounted for up and down reciprocal motion on a double acting raise or elevating air cylinder 3! which is mounted in a sub-frame 32 carried by front plate ll of main frame it. Guide means to insure that the table 33 is always horizontal is provided which includes a transverse shaft 33 journaled in brackets depending from the table 30 and carrying rigidly attached gears on opposite ends, one of which is seen at 3 The gears 34 mesh with racks, one of which is seen at 35, which are attached .to an upstanding plate of the sub-frame 32.

On the front the platform carries a pair of plain rollers, one of which is seen at 36, there being one adjacent each end thereof, the rollers 36 cooperating with plain track bars, one of which is seen at 31, which are carried on the front plate of the sub-frame 32. The shaft 33, gears 34 and racks 35 insure movement of the table 33 in parallelism, and the rollers 36 and tracks 31 guide it and prevent rotation thereof, at the same time insuring intermeshing of gears 33 and racks 35.

At opposite sides of the table 33 there is duplicate mechanism, that on the right-hand side being illustrated particularly in Fig. l of the drawings, which shall now be described, it being understood that similar mechanism is present on the left-hand side. Slidably mounted in guide means 38 (see Fig. 2) carried by the table 33 is a base frame 39 which is adjustable on a horizontalv axisparallel with the axis of the pins I9 and'with the axis of the plungers ill and 88. A common adjusting rod 43 has threaded relation with the two base frames, one of which is seen at 39, and by rotating said rod 40 said base frames may be simultaneously adjusted toward or from each other.

Slidably mounted on the base frame 39 is a high frequency transformer support ll which is slidably adjustable by a double acting air cylinder 42, the cylinder of which is also mounted on the base frame 39 and the piston of which is attached to the transformer support M. The support ll carries. a high frequency transformer 43, there being a similar high frequency transformer fi l mounted on the opposite side of the machine which is controlled by a double acting air cylinder :35 (see Fig. 3) which is similar to cylinder 32 and is mounted on a separate base frame similar to base frame 39, as above mentioned.

The high frequency transformers 33 and 44 are provided with similar single loop fluid cooled induction heads or inductors 46 and 41, respectively, which selectively are adjusted to encircle the unheaded end of a pin it] and to heat it for a predetermined period so as to bring it up to a temperature at which it can be readily riveted, after which the head 13 or M, as the case may be, is moved axially of the pin l9 and then lowered to be out of the way of the plungers, headers of riveters ll and it which are simultaneously moved toward each other against the pin l9 to form a head on the previously heated portion.

Many of the features of the high frequency transformers 43 and 44 and the induction heads 36 and H, as well as some of the features of the control circuit therefor, are involved in induction heating apparatus known commercially as Tocco Junior manufactured and sold by the Ohio Crankshaft Company of Cleveland, Ohio. However, there have been a number of important modifications of the standard circuitof the 'I'occo Junior and the particular assembly of mechanical parts above described is entirely different from the Tocco Junior unit.

Before proceeding with a description of the air, hydraulic and electrical circuits, it may be well to describe briefly the successive steps in-' volved in a typical case of riveting pins of a chain. As previously mentioned, the chain 20 is preferably assembled with the unheaded ends of the pins i9 projecting successively on opposite sides of the chain 23. The chain is then laid on the platform 2i and the parts will be essentially in the positions illustrated in Figs. 1 and 2, ex-

cept that the double acting cylinder 31 will be in its lower position instead of its upper, position, as illustrated, and consequently the-table30 will 1 be lowered, with the transformers .43 and 44 and the inductors 4t and ll lowered entirely below the.

plungers if and it. In addition, the chain 20 will be considered in a position where it is necessary to move it forward the length of one link to bring a pin IS in position to be riveted.

The first operation is energization of the double acting feed cylinder 21 which will move the chain 23 forward to position a pin I9 in alignment with the plungers, headers or riveters H or l8. Thereafter the double acting feed cylinder 21 reverses its operation and is prepared to move the chain forward to align the succeeding pin. The raise or elevating cylinder 3| is then energized to raise or elevate the table 30 and the transformers 43 and A l and the inductors 46 and 41 into the positions illustrated in Fig. 1 of the drawings. Thereafter double acting air cylinder 42 or its counterpart E5 is energized to slidethe inductor 53 or ll over the unheaded end of the pin l9, only one of these cylinders 42 or its counterpart being thus energized, depending upon whether the unheaded end of the pin- [3 extends to theright or left.

As illustrated in Fig. 1 of the drawings it will be the lefthand cylinder 415 which is similar to cylinder 42 which will be thus energized, and the loop type head or inductor M will move over the aligned unheaded end of pin i3 which projects beyond the adjacent side bar of the chain 20. When the inductor or head ll is thus positioned, it will be energized for a predetermined length of time adequate to heat locally the unheaded end of pin l9 by induced high frequency electrical current. After a predetermined time, which may be adjusted by controllinga timer, the head All and transformer 33 will be moved to the left (as seen in Fig. 1) under the action of the double, '7

acting cylinder 45 to remove the head or loop 47 from the heated unheaded pin end. Thereafter, elevating or raise cylinder 3| will be actuated to lower the table and thus lower the transformers 43 and 44 and their inductors 46 and 41 so that the latter are entirely below the plungers I! and I8. Hydraulic rams I3 and I4 are then simultaneously energized by hydraulic fluid under high pressure so that the plungers I! and I8 move toward each other, plunger I1 contacting the previously formed head on pin I9, and plunger I8 forming a head on the heated end of said pin l9. The contacting faces of the plungers I1 and I8 are preferably cupped or recessed so as to form a head on the heated end of pin I 9 in the one instance and to conform to the previously formed head on the pin I9 in the other instance.

After the plungers I1 and I8 have moved toward each other and compressed the pin I9 between them so as to build up a predetermined hydraulic fluid pressure in the conduits or feed lines leading to one of the hydraulic rams I3, I4, the plungers I1 and I8 are retracted to the positions illustrated in Fig. 1 of the drawings and the machine is ready to complete another cycle of operation, as above described.

Attention is now directed to Fig. 3 of thedrawings which illustrates the hydraulic rams I3 and I4 and the hydraulic circuit which controls them and also illustrates the various air cylinders and their control circuits. An air line, pipe or conduit 48 is provided and delivers air under pressure to the several cylinders 27, 3|, 42 and 45 under the control of individual valves. For example, solenoid actuated valve SI is provided for feed cylinder 27, the valve being of standard construction and spring biased so that when its solenoid is deenergized it will deliver air to move the piston of cylinder 21 to the right or, in other words, retract it. Conversely, when its solenoid is energized the cylinder 21 will be expanded or the piston moved to the left. There is an automatic returning limit switch LSI associated with cylinder 21 and which is actuated when the piston thereof reaches the end of its stroke, automatically resuming its normal position when the piston is returned.

Associated with and controlling double acting cylinder 45 is a solenoid actuated valve S3 which is similar to the valve SI above described. There is a similar valve S4 associated with and controlling double acting cylinder 42. Associated with cylinders 45 and 42 are normally closed limit switches LS2 and LS3, respectively, which are open when their respective cylinders 45 and 42 are in their retracted or out positions, that is, when they have moved the inductors 4G or 41, as the case may be, outwardly to the positions illustrated in Fig. 1 of the drawings.

The double acting air cylinder 3| is controlled by a solenoid actuated valve S2 which is similar to valves SI, S3 and S4. Associated with the piston rod of double acting cylinder 3| are limit switches LS4 and LS5. Switch LS4 is a double contact switch, one of the contacts of which is normally closed, the other normally open, said switch being actuated when the piston rod of cylinder 3! is retracted. Switch LS5 is normally biased to its open position and is closedwhen the piston of cylinder 3| reaches the upper limit of its stroke.

It is, of course, evident that all of the solenoid operated valves SI, S2, S3 and S4. control the delivery of air from air line 48 to their respective 6 double acting cylinders and at selected ends thereof while, of course, venting the opposite side of the cylinder to atmosphere whenever a cylinder is actuated.

The hydraulic circuit for controlling the hydraulic rams I3 and I4 includes a pump 49 which derives hydraulic fluid, such as oil, from a tank 50 and delivers it over a pressure line or conduit 5| to a control valve 52 which is biased to a central no-load by-pass position and which may be reversely operated by either of the solenoids S5 or S? which reversely control the core thereof.

If solenoid S5 is energized, valve 52 will be actuated so as to deliver hydraulic fluid under pressure to conduit 58, which has two branches I58 and 258, energizing hydraulic rams I3 and I4 to cause the plungers I! and I8 to move inwardly or toward each other. Once this movement is started it will normally continue until a predetermined pressure is built up in the hydraulic conduit 58 and branches I58 and 258 adequate to actuate combination pressure relief valve and control switch PSI which provides a pressure relief by-pass to the tank 58 over an obvious pipe or conduit. That is, predetermined pressure in conduit 58 and branches I58 and 258 will cause relief valve PSI to open and will simultaneously close an electric switch for a purpose hereinafter described.

If solenoid S1 is energized the hydraulic fluid under pressure will be delivered to the pipe or conduit 59 to energize rams I3 and I4 to move the plungers I7 and i8 outwardly or away from each other and their movement will automatically continue for the full stroke, whereupon combination pressure relief valve and electric switch PS2 will be actuated to by-pass the hydraulic fluid to tank 58 and to actuate the electrical switch of PS2.

To provide for the simultaneous movement of the plungers I? and i8 at substantially the same rate toward each other, there is a rotary hydraulic motor in each of the branch conduits I58 and 258 designated 65} and 6!, respectively, which are coupled together by a flexible coupling 62. This arrangement insures substantially equal flow of hydraulic fluid in the two branch conduits I58 and 258, thus insuring substantially the same rate of movement for the plungers I1 and i8.

To take care of any inequality or leakage, there is a pressure relief valve connected across the input and output lines of branch conduits I58 and 258, the relief valve for the former being designated 63 and that for the latter being designated 64. These valves are set at a relatively low pressure, such as one hundred and fifty pounds per square inch, sov that if either plunger H or iii reaches the end of its stroke before the other, valve 83 or 64 associated with the ram l3 or I4, which has not finished its stroke, will open and allow hydraulic fluid to by-pass the metering motor E8 or 6!, as the case may be, causing said slow plunger I! or I3 to finish its complete stroke. If hydraulic fluid under pressure is delivered to the conduit 59 to retract the plungers I! and it, the branch conduits 58 and 258 and the conduit 58 provide a return path for the hydraulic fluid which is delivered to the tank 50 through control valve 52. The return movement of the plungers ll and I8 is not metered through the motors 60 and 6| but is by-passed through return check valves in the relief valves-(i3 and 64. If the hydraulic fluid under pressure is delivered to the conduit 58, conduit 59 will be the return conduit and valve '52 will deliver it to tank 50.

frequency Fig. 4 of the drawings illustrates the wiring diagram of the electrical circuit in which the limit switches and solenoid operated valves of Fig. 3 are included diagrammatically. The electrical circuit includes three principal parts which are interconnected in a manner obvious from the following description. Said circuit includes an alternating current motor 65 which is energized from three power line 66. Motor 65 drives a high alternator or generator 61 which in the T0000 Junior unit previously mentioned and in the system of the instant invention may develop alternating electrical current having a frequency of approximately ten thousand cycles per second, which is delivered to high frequency transformers 43 and 44, selectively, and to inductors 46 and 41, selectively, which are permanently connected to the secondaries of said transformers 43 and 44. Capacitators or condensers '68 are connected across the primary terminals of transformers 43 and 44, respectively, to improve the power factor. The control circuits by which transformers 43 and 44 are selectively energized for predetermined times during the cycle of operation of the riveting machine will be described hereinafter.

Branching from two of the power lines 66 is a single phase line ill which delivers power to mains H and 12 which are the mains for the principal control system. Line l also energizes a transformer 13, the output of which energizes mains 14 and 15 of an auxiliary control circuit.

It may be stated that a number of the standard electrical parts of the Tocco Junior unit are not illustrated in the wiring diagram as they form no part of the present invention. It may also be mentioned that the reason for the two separate mains H, 32 and l4, 15 is that in the commercial unit the former is of 220 volt circuit and the latter 110 volt circuit; the transformer 13 therefore being a two to one step-down transformer.

The individual circuits of the electrical control system can best be described in connection with a description of one complete cycle of operation which shall now be given. Upon closing a master control or disconnect switch for the three phase power line 66, it is evident that motor 65 will be energized, thereby developing high frequency electrical voltage by generator Bl. Mains ll, 12 and l4, l5 will likewise thus be energized. The automatic pin riveting machine is then in condition to be set into operation and once set into operation it will continue to operate automatically to rivet the successive pins I9 until it is stopped, there being certain flexibility as shall be pointed out in the description to follow.

Automatic operation is initiated by closing manual switch MSI which energizes the light Ll indicating that the system is in automatic operation. The initial starting of the automatic operation requires the operator to close push button PBI which energizes the solenoid or coil of relay CI over an obvious circuit. Coil or solenoid of relay Cl is held energized over an obvious circuit including the upper normally open contacts of relay Cl and the upper normally closed con.- tacts of limit switch LSl. The lower normally open contact of relay Cl on closing energizes solenoid valve SI which causes the feed cylinder 21 to move forward and advance chain with the pin 19 in position to be riveted. At the forward end of its stroke the feed cylinder 21 actuates limit switch LSl which breaks the hold circuit for the relay Cl, causing it to deenergize, which deenergizes the solenoid of valve SI, thereby causing the feed cylinder 2'! to retract to its 8 initial feeding position where it will be ready to feed the chain 20 forward another link length when subsequently energized at the start of an other cycle.

Simultaneously with the release of relay Cl by operation of limit switch LSI it closes a circuit through its lower and normally open contacts to energize the coil or solenoid of a relay C2 which is provided with a hold circuit through its upper normally open contacts and through the upper normally closed contacts of relay C5 over an obvious circuit. Relay C2 in energizing closes the circuit of solenoid valve S2 over its lower normally open contacts.

As previously described, solenoid $2 on being energized causes raise or elevating cylinder 3| to expand, raising the table 30 and the transformers 43 and 44 and inductors 46 and 41 to the position illustrated in Fig. 1 of the drawings, with the axes of the loop inductors or heads 46 and 41 in alignment with the axis of the pin l9 to be riveted and the axis of the plungers or headers l1 and I8.

When the table 30 and parts which it carries are also elevated or raised, limit switch LS5 (found to the left of the wiring diagram) is actuated and this energizes a magnetic clutch 19 of a standard motor driven timer TRI, the effect of which is to connect a cam to the shaft of the continuously running motor of said relay so that the cam will start to rotate. It may be stated that the motor of the relay TRI is directly across the mains 14 and 15 and runs continuously once the main switch of the system is thrown. Furthermore when the switch LS5 is energized it not only actuates the clutch 19 to start the timing cam into operation, but it effects an initial closing of the normally open contacts of relay TR! and these contacts remain closed until the motor 80 has rotated the cam of the relay for a predetermined time which may be adjusted by an operator.

Thus immediately upon the energization of clutch 19 in response to closing of limit switch LS5 the two normally open contacts of the relay TRI are closed, the upper providing a holding circuit for the clutch until the cam has rotated a predetermined amount, and the lower closing an obvious circuit for the coil or solenoid of relay C9, closing its three normally open contacts. The center contact of relay C9 closes an obvious circuit through the coil or solenoid of relay C5 which closes its bottom normally open contact and opens its top normally closed contact, the latter breaking the holding circuit of the coil of relay C2. The coil or solenoid of relay C2 is, however, held in energized condition over an obvious holding circuit directly through the lower, now closed contact of relay C5, thus maintaining the table 30 and all the elements carried by it in the elevated position illustrated in Fig. 1. It may be stated that the timer TB! is a standard unit on the T0000 Junior previously mentioned.

The upper and lower contacts of the relay C9 operate to close a circuit either to the solenoid of relay C3 or to the solenoid of relay C4 over obvious paths, depending upon the position of the contact of alternately shiftable relay designated S6, of which a cam operated Struthers- Dunn relay of standard design is an illustration. This relay S6 includes a shiftable switch element 16 which is connected to main H and which is operated by cam 11 so that every time the solenoid of relay S6 is energized the switch element 16 moves alternately to one contact or another.

9 In the positionof the switch element 16 illustrated in Fig. 4 of the drawings the relay C3 is energized through the upper contacts of the relay C9. Also the signal light L2 is energized to indicate the position of the switch element 16 and, what is of particular significance, to indicate which of the inductors 46 or 41 is to be energized.

Relay C3 on energizing closes its two normally open contact-s, the upper one of which energizes the solenoid of heavy duty contactor or relay S8 in a high frequency circuit which energizes the transformer 43 and the inductor 41 from the high frequency generator 61, over an obvious circuit which includes the normally closed contacts of a relay ICRI which is in the left-hand control circuit and which is now closed due to the fact that its coil is connected in parallel with the coil C9 and consequently is energized simultaneously therewith by the lower contact of the timer relay TRI. There is also a signal light 18 connected across the terminals of the coils of relay C9 and ICRI, thus indicating they are energized.

The lower contact of relay C2 energizes the solenoid of control valve S3 which energizes air cylinder 45 to move the high frequency transformer 44 and inductor or head 41 to the right, as viewed in Fig. 1 of the drawings, thereby causing the inductor 41 to encircle the unheaded portion of the pin I9 which is to be heated by electrical high frequency induced heat.

At the end of the heating time determined by the timer 'I'Rl its two contacts are open, thus deenergizing relays C9 and ICRI and deenergizing the transformer 44 and inductor 41. The deenergization of relay C9 breaks the previously described circuit for the solenoid of relay C5. However, said solenoid of relay C has two very obvious. circuits which include limit switches LS2 and LS3. Limit switches LS2 and LS3 are biased to closed position, but they are open when the two transformers 43 and 44 and inductors 46 and 47 are in the retracted positions, as illustrated in Fig. 1 of the drawings and as previously described. However, since transformer 44 and inductor 41 have moved to their inward positions under the conditions previously described, limit switch LS2 will be closed and thus provide a holding circuit for the solenoid of relay C5. This relay will remain energized until air cylinder 45 is energized to move the transformer 44 and the inductor 41 to the left or outward, which will open limit switch LS2, thus breaking the holding circuit for the coil of relay C5 since limit switch LS3 is already open because cylinder 42 is in its contracted or outer position.

The deenergization of relay C5 breaks the previously described holding circuit for the coil of relay C2 involving the lower contact of rela C5, thus deenergizing relay C2 which opens the circuit to solenoid S2 which returns to its normal position and actuates elevating cylinder 3| to lower it.

At the beginning of the cycle, when raise cylinder 3i first started to raise the table 30 it released limit switch LS4 so that it moved to its normal position as illustrated in Fig. 4 of the drawings which energized the coil of relay C5 over an obvious circuit including normally closed upper contacts of pressure switch PSI. After the inductor 41 had heated the unheaded end of pin 19 for a time determined by the relay TR!, and the table 30 was lowered as above described, limit switch LS4 was actuated by the contraction of cylinder 3|, breaking its lower contacts, However, relay C6 is provided with a holding circuit which by-passes the lower contacts of limit switch LS4 through the lower contacts of said relay C6, thus holding relay C6 energized for the time be- When limit switch LS4 is actuated on the return of the table 30 to its lower position, its upper contacts are closed and they energize the solenoid or coil of relay Cl through the upper contacts of relay C6 which is now energized. Relay C! on energizing closes the circuit through its lower contacts and a control switch MS2 to energize the operating solenoid of the Struthers-Dunn relay SS, thus switching the switch element 16 from the position shown to its alternate position where the light L3 is energized and relay C4 is energized instead of the relay G5, on the subsequent operation of the timer TRI and relays C9 and ICRI during the next heating cycle, the purpose, of course, being to energize the transformer 43 and inductor 46 on the next heating cycle as the pins I 9 are successively extended through the chain 28 in opposite directions.

With the inductors 45 and 4! lowered out of the paths of the plungers l1 and I8 and with the unheaded end of the pin 19 heated to a very high temperature which, for example, may be of the order of l600 to 2200 Fahrenheit, the relay C! on energizing, in addition to operating the relay S6, also energizes solenoid valve S5 over its upper contacts which controls the hydraulic valve 52, as above described, to supply hydraulic fluid under pressure to the line 58 and the branch lines I58 and 258 to move the plungers, headers or riveters I! and I8 inwardly against the pin l9 and to form a head on the heated unheaded end of said pin l9, since the headers l1 and I8 are formed as dies for this purpose.

The headers l1 and I8 are preferably designed or shimmed with a predetermined length so that in completing their riveting operation the pistons of the rams I 3 and I4 travel the full stroke thereof. After both said rams l3 and I4 have traveled their full stroke, pressure in the lines 58, I58 and 258 will build up and actuate the combination high pressure relief and pressure responsive switch PSI which opens its normally closed contacts and deenergizes the coil of relay C6, thus deenergizing relay Cl and solenoid valve S4.

Pressure responsive switch PSI through its normally open contacts which are closed in response to pressure above mentioned, energizes the coil of a relay C8 through the normally closed lower contact of pressure responsive switch PS2 associated with the conduit 59. Relay C8 has a holding circuit through its normally open upper contacts and the normally closed lower contacts of pressure switch PS2, thus holding it independent- 1y of pressure switch PSI. The lower contacts of relay C8 energize solenoid valve S! which operates valve 52 to deliver hydraulic fluid to the conduit 59 and connects conduit 58 to tank, thereby moving the plungers I1 and I8 outward. After they have both moved outward to the ends of their stroke, hydraulic fluid pressure will build up in conduit 59 to actuate the pressure responsive switch PS2 which at its lower contacts breaks the holding circuit for relay C8, deenergizing it, which in turn deenergizes the operating solenoid S1 for hydraulic valve 52, allowing it to return to neutral and providing a no-load by-pass for the pump 49.

The relay C7 previously mentioned, which controls the Struthers-Dunn relay S6 so that inductors 46 and 4! are normally alternately energized,

effects this control through its lower contacts and manual switch MS2 previously mentioned. In case the pins l9 are all extended through the chain 20 in the same direction, that is, with all heads on one side of the chain, manual switch M82 is left in its open position, as a consequence of which the energization of coil Cl will not actuate the relay $8. In this case the inductor 46 or 41, as the case may be, will be successively returned and positioned over the pins to heat them rather than the normal alternate operation. Also in case a pin i9 is presented at the operating position in which the unheaded end extends in the wrong position, as determined by the lighting of light L2 or L3 which indicates which of the inductors 46 or 41 is .to be energized, it is only necessary for the operator to push the button PB3 which will manually energize th Struthers- Dunn relay S3 and reverse the position of the switch element 16, thereby selecting the other of the inductors 4B or 41 to be energized.

After the machine has completed one cycle of operation it will normally proceed with succeeding cycles. To effect this the manual switch MSl, above mentioned, is left closed. When the switch PS2 is actuated following the outward movement of the plungers I1 and 18 it closes its upper contacts which are in series with manual switch M55 and push button P32, and energizes the coil of relay Cl, starting a new cycle of operation following that previously described.

If it is desired to terminate the operation of the machine following one complete cycle, manual switch MS! is left open. Furthermore, if the operator desires merely to terminate the automatic operation of the machine following the completion of any cycle, it is only necessary for him to push the button PBZ and hold it depressed until the cycle automatically completes. Thereafter, he can release push button PB2 but the machine will not automatically start in operation again until push button PB! is pushed to actuate relay CI, as previously described.

In the previous description it was assumed that the Struthers-Dunn relay S6 was in such a position that it closed the circuit through switch ele ment 16 to relay C3.

In the normal operation the succeeding cycle will take place the same as the first cycle, except that switch element 16 would move to energize light L3 and upon the operation of relays C9 and ICE! the coil of relay C4 would be energized instead of the coil of relay C3; During this cycle relay C4 through its upper contacts energizes solenoid valve S4 to move the cylinder 42 inward, thus moving the inductor 48 over the unheaded end of a pin I9. The lower contact of relay C4 will energize the solenoid of heavy duty contactors S9 and thus energize the inductor M from the high frequency generator 6! through the contacts of relay ICRI which are also closed.

The second cycle of operation is therefore essentially the same as the first, except for the inward movement of the inductor 46 instead of the inductor 41, together with the associated transformer 43 instead of the transformer 44, and with the energization of said transformer 43 and inductor 46 instead of the transformer 44 and inductor 41.

As previously described, the relay TR! has a variable predetermined cycle of operation which determines the heating time for the pins. This heating may be determined at any time by manually releasing the clutch 19 through a normally closed push button switch 81 which is in series therewith, the efiect of actuating push button 8| (iii 12 being the same as though relay TRI completed its normal cycle of operation.

From the above description it is evident that the invention in its most specific aspect is directed to apparatus for the riveting of chain pins. In certain broader aspects, however, it is evident that this is only one illustration of a forging operation of a metal, the metal must be essentially one containing iron so that the induced high frequency currents will develop induced heat in a well known manner. In a still broader aspect of the invention, forging need not take place, but the mere heating of the iron of a metal element may be involved as a part of a heat treating process.

Obviously those skilled in the art may make various changes in the details and arrangement of parts without departing from the spirit and scope of the invention as defined by the claims hereto appended, and I therefore wish not to be restricted to the precise construction herein disclosed.

Having thus described and shown an embodiment of my invention, what I desire to secure by Letters Patent of the United States is.

1. An automatic pin riveting machine including a support for a chain having unheaded pins to be riveted, a pair of spaced aligned rams having pin riveting heads positioned to move toward and away from each other and to rivet a heated pin when moved toward each other, a pair of electrical heaters, means operable to position a selected heater adjacent an unheaded pin and to heat it, means for removing said heater from the heated pin, and means to feed said rams to clamp the heated pin between them and rivet the pin to the chain.

2. An automatic pin riveting machine including a support for a chain having unheaded pins to be riveted, a pair of spaced aligned rams having pin riveting heads positioned to move toward and away from each other and to rivet a heated pin when moved toward each other, a pair of inductor coils, means operable automatically to position a selected inductor coil over an unheaded pin and to heat it by induction, means for automatically removing said inductor coil from the heated pin, and automatic means to feed said rams to clamp the heated pin between them and rivet the pin to the chain.

3. A pin riveting machine including a chain support, a ram, means for positioning a chain on said support with an unriveted pin aligned with said ram, a loop electrical heater, means for moving said loop heater to a position over and encircling the end of said unriveted pin to heat it, means for removing said heater from said pin after it is heated, and means for energizing said ram to rivet said pin, all said means operating automatically under the control of control mechanism.

4. A pin riveting machine including a chain support, a ram, means for positioning a chain on said support with an unriveted pin aligned with said ram, a loop electrical heater, means for moving said loop heater to a position over and encircling the end of said unriveted pin to heat it, means for removing said heater from said pin after it is heated, and means for energizing said ram to rivet said pin after said loop heater is removed.

5. A chain pin riveting machine including a pair of opposed, aligned spaced apart hydraulic rams, a support for a chain constructed to position a chain pin in a plane passing through said rams, means for feeding said chain to align said pin with said rams, a pair of high frequency electrical transformers each having an inductor head adapted to be positioned over an unheaded end of a chain pin, the two transformers and inductors being positioned to head oppositely projecting pin ends, a vertically adjustable platform, horizontally slidable frames on said platform, each carrying one of said transformers and its inductor, means for elevating and lowering said platform first to position the inductor in alignment with a pin and thereafter to remove it from said position, means for reciprocating a selected one of said frames first to position an inductor over a pin and thereafter to remove it therefrom after it is heated, and means for energizing a selected transformer and inductor to heat the associated pin end.

6. A chain pin riveting machine including a pair of opposed, aligned spaced apart rams, a support for a chain constructed to position a chain pin in a plane passing through said rams, means for feeding said chain to align said pin with said rams, a pair of high frequency electrical transformers each having an inductor head adapted to be positioned over an unheaded end of a chain pin, the two transformers and inductors being positioned to head oppositely projecting pin ends, a vertically adjustable platform, horizontally slidable frames on said platform, each carrying one of said transformers and its inductor, means for elevating and lowering said platform first to position the inductor in alignment with a pin and thereafter to remove it from said position, means for reciprocating a selected one of said frames first to position an inductor over a pin and thereafter to remove it therefrom after it is heated, and means for energizing a selected transformer and inductor to heat the associated pin end.

7. A chain pin riveting machine including an electrical heater adapted to be moved to a position over and encircling an unheaded pin end and heat it, means operable automatically to position said heater over a stationary unheaded pin end and heat it and thereafter to remove it therefrom, and ram means operable to form a head on the heated end of said pin.

8. A chain pin riveting machine including an electrical loop inductor adapted to be positioned over and encircling an unheaded pin end and heat it, means operable to position said inductor over an unheaded pin end and heat it and thereafter to remove it therefrom, and hydraulic ram means operable to form a head on the heated end of said pin.

9. Mechanism for heating a rod or shaft end containing iron, including means for supporting said rod or shaft end in a predetermined position, a loop inductor, means for moving said loop inductor to a position over and encircling said rod or shaft end, means for energizing said loop inductor with high frequency electrical current to heat said rod or shaft end by induction, and means for removing said loop inductor from the heated rod or shaft while said rod remains in said predetermined position.

10. Mechanism for forging a metal element containing iron which includes means for positioning and supporting said element in a predetermined position, a loop inductor, means for automatically extending said loop inductor over said metal element, means for energizing said loop inductor with high frequency electrical current to heat said metal element by induction, means for automatically removing said loop inductor from the heated element While the latter remains in said predetermined position, and means for automatically forging the heated element to alter its shape.

FRED J. WRIGHT.

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

UNITED STATES PATENTS Number Name Date 1,308,399 Cutter July 1, 1919 1,878,458 Blanchet Sept. 20, 1932 1,901,334 Reed Mar. 14, 1933 2,275,763 Howard et 'al Mar. 10, 1942

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