US2444787A

US2444787A - Machine for forming material

Info

Publication number: US2444787A
Application number: US555027A
Authority: US
Inventors: George D Rechton; Delbert J Ward; Jack H Watson
Original assignee: Douglas Aircraft Co Inc
Current assignee: Douglas Aircraft Co Inc
Priority date: 1942-09-07
Filing date: 1944-09-20
Publication date: 1948-07-06
Anticipated expiration: 1965-07-06

Description

July 6, 3948 G. D. REcHToN ET AL MACHINE FOR FORMING MATERIALS Original Filed Septv. 7, 1942 N NN R fatentecl July 6, 1948 NITED STATES yENT CFFICE MACHINE FOR FORMNG MATERIAL Original application September 7, 1942, Serial Divided and this application Sep- `tember 20, 1944, Serial No. 555,027

Claims. l

rThis invention relates to a machine for formlng sheet material, and more particularly to an automatic machine for forming sheet materials which can be eiiiciently used by inexperienced personnel.

This application is a division of our application Serial No. 457,63),Machine for forming material, led September 7, 1942, now Patent No. 2,372,516.

In the illustrated embodiment of the machine of the present invention the forming operation is produced by a pair of forming tools which are mounted for relative movement and which cooperate to bring about the desired forming action. One of the tools s controlled by an Operator which is so formed that it is operative to actuate the tool only after the tool has been moved into contact with the work piece and is applying a predetermined pressureto the same.

To render the operator operative, means are provided iormovng the sameto cause the tool controlled thereby to move into progressively increasing pressural engagement with the work piece. The means for moving the tool controlled by the operator into engagement with the work piece comprises a spring-loaded pivoted lever normally holding the operator with its tool oui-of work-engaging position. The tool is moved into work-engaging position by a pneumatically operated piston connected to the lever and adapted to rock the same against the spring to move the operator and force the tool into engagement with the work.

The air supplied to the cylinder of the rpiston is regulated by an electrical control system in-` cluding a pair of solenoids, the circuits of which are controlled by relay operated switches. The solenoids control inlet and exhaust valves and are so associated with the valves that th'e latter are open when the solenoids are energized.

A manually operable switch under the control ci the operator of the machine when closed results in the energization of the inlet valve solenoid to bring about movement of the piston and the lever interconnecting the same and the tool operator to urge the tool carried by the latter into engagement with the work. The tool operator after it has been moved at a distance sufficient to Cause the too-l controlled thereby to apply the predetermined pressure against the work will apply a, percussive force to the tool to complete the forming operation.

As the percussiveiorce applied by the actuator is adjustable, work pieces of different materials as well as shapes and sizes can be effectively formed by the machine of the present invention.

After the actual forming operation hasbeen completed the operator of the machine opens the manually operable switch which de-energizes the relay resulting in the opening of the circuit of the solenoid controlling the inlet valve and thefclosing of the exhaust solenoid circuit. The energization of the exhaust valve solenoid opensthe exhaust valve and the spring pressed lever. returns the piston to its normal position and the actuator is moved to the position in which the tool controlled thereby is out of engagement with the work piece.

The machine is capable of high production being limited only by the movement of the work piece into and out of the work station of the machine as the only skill necessary tothe eincient operation of the machine is the ability to ascertain whether the work is properly aligned with the forming tools prior to the forming operation. Therefore, personnel having little or nol mechanical experience can successfully be assigned to the machine.

Other features and advantages of the machine oi the present invention will be apparent from the following description taken in connection with the accompanying drawings, in which:

Figure l is a side elevation of a machine embodying this invention;

Figure 2 is a iront elevation of the machine shown in Figure 1; and

Figure 3 is a schematic view showing the forming devices, the pneumatic mechanismfor their operation, and a wiring diagram for the control of the pneumatic mechanism.

While a dimpling machine has been selected to disclose this invention, it will be understood that, as to some of its features, the invention is not restricted to a dimpling machine but is applicable to other forming machines.

Figures 1 and 2 show a dimpling machine Ill having a base il upon which is mounted asupporting column I2. A pair oi generally horizon,- tal laterally extending arms I3 and I4 are clamped to the column l2, the upper arm I3 supporting at its outer enda pneumatic tool oper-v ator it and the lower arm I4 supporting atits outer end a lower dimpling anvil assembly I 6.

The tool operator l5 is mounted for vertical` movement in the guide I8 at the outer end of the upper arm I3 by a lever I9 which is fulcrumed at 2 Iv between ears 22 extending upwardly from the upper arm it and which is connected at its outer end to the upper end of the tool operator I5 at 23, and is connected at its inner end to a. piston 3 rod 24 of a piston 25 (shown only in Figure 3) which reciprocates within a pneumatic cylinder 26 mounted upon the rear end of the upper arm I3. The lever I9 is spring loaded by a spring 21 compressed between a stationary lug 28 and a collar nut 29 on a bolt 3| which passes through an eye in the lug 28 and is pivoted at its outer l end to the free end of a depending arm 32 on the lever I 9. As the spring 21 tends to move the left Y end of the lever I9 downwardly as viewed in Figure 1, stop bar 33 is mounted on the arm I3 to engage the under side of the rear end of the lever I9 to prevent the piston 25 from striking the bottom of the cylinder 26.

VThe lower end of the tool operator I5, carries a forming tool or female die 34 and is surrounded by a heating element 35 of annular form. The heating element 35 is held in position laterally with respect to the tool operator I5 and supported vertically by =a piston 35 which is vertically reciprocably'pmcvable within a pneumatic cylinder 31 mounted upon the outer end of the upper arm I3 adjacent the inner side of the tool operator I5. Admission of air to the pneumatic cylinder 31 moves the heating element downwardly and upon exhaust of air from this cylinder,` the heating element is retracted to its normal position by the action of a tension spring 38 secured at its upper and lower ends to the guide IS'andpiston 36 respectively. A cable 39 contains the-electrical conductors for heating the element 35 and registering its temperature.

Io the upper face of the outer end of the arm I 4is secured a pneumatic cylinder 40 to which air'is supplied at an inlet 4I. A tubular piston 42 reciprocates in the cylinder and carries at its upper vend a heating element or heating body 43 which is apertured for the accommodation of the stationary male dimpling die I6. The support for the die I6 extends downwardly through the piston 42 and is mounted` upon the lower arm I4. The heating element 43 is thus vertically slidable with respect to the stationary dimpling die-"I3 from a lower retracted position to an upper position in which it makes contact with the metalsheet to be dimpled. A cable 44 contains the conductor wires for supplying the energy to heat the heating element 43 and to register its temperature.

f The heating elements 35 and 43 per se or their use as heating elements form no part of the present invention, being disclosed` and claimed in our copending application above identified. The heatinig element'l, in the illustrated embodiment of the machine of the present invention, closes a microswitch 45 connected to the control mechanism by a cable 41. The

cables

44 and 41 lead toa junction box 48 from which electrical connections are made to the control and indicating devices by the cable 49.

"The system of air conduits and pneumatic control devices for operation of the

pneumatic cylinders

26, 31, and 40, and for operation of the pneumatic cylinder 5I of the tool operator I5, are shown schematically in Figure 3, some of the conduits and control devices appearing in the structural views, Figures 1 and 2. Air enters the machine'under pressure 52 through a gate valve 53 and 'may proceed to an electrically controlled valve 54 through the pipe 55 and thence, when valve 54 is opened, through a pipe 55 to cylinder 26'to actuate the lever I9 to depress the tool operator I5.

Air vmay also pass from the gate valve 53 to the electrically controlled valve 51 through pipe 58, for transmission when valve 51 is in open position through supply conduit 59A and then pipes 65 and 5l to cylinders 31 and 4l respectively for movement of the heating elements 35 and 43 respectively from their retracted position to their position of contact withthe metal sheet to be dimpled. Electrically controlled

exhaust valves

52 and 53 lare in closed position when

valves

54 and 51 respectively are in open position, and vice versa. They function to relieve the air pressure in cylinder 25 and in cylinders 31 and 4I) respectively forY the elevation of the dimpling gun in the case of cylinder 26 and the retraction of the heating elements 35 and 43 in the case of the cylinders 31 and 4U.

A valve 64 and a pressure gauge 51 in the supply conduit V59 leading to the T connection 65 joining the conduit 59 and the pipes 60 and 6I provide means for regulating the air pressure transmitted to cylinders 31 and 4U at any desired value, thus regulating the degree of pressure at which the heating elements engage the metal sheet. 'I'he section of exhaust pipe in which exhaust valve 52 is placed, the air supply pipe 55 and the pipe 5S leading to the cylinder 26 are connected as shown by a T 68. The exhaust pipe in which valve 53 is placed, the air supply pipe 58 and the conduit 59 leading to the T 66 are connected as shown by means of a T 69.

To T 1I interposed in the air supply pipe 55 is connected `a pipe 12 leading to a pressure regulating valve 13, which in conjunction with a pressure gauge 14 serves to regulate the air pressure in pipe 15 leading to the cylinder 5I of the tool operator l5 and tripping the pneumatic firing device for applying an impulse force to the dimpling die when the pressure between the upper and lower dimpling dies reaches a prescribed value after the tool operator has been lowered and the two dies brought into engagement with the metal sheet to be dimpled through depression of the tool operator I5 bythe lever I9 upon actuation of the piston 25 operating in cylinder 26.

Upon an angle support 16 secured to the upper arm I3 is mounted a control box 11 which houses the electrical control equipment for sequential control of the electrical devices for the actuation of Valves 54, 62, 51, and 63. These devices and their connections are enclosed within dash lines on Figure 3 and designated by the numeral 18. The

valves

54, 62, 51, and 63 are electrically actuated by solenoids in a manner to be hereinafter explained, the conductors from the control box 11 to the various valve operating solenoids passing through a connection box 19 mounted on the inner end of the upper arm I3.

The front face of the control box 11 serves as a control panel 8l upon which are mounted the several dial switches and other manual controls, and the value registering instruments for use in operating the machine. These several control devices and registering instruments will be referred to and described in the course of the following explanation of the wiring diagram of Figure 3. On this diagram the arrows indicate the direction of potential drop.

Electrical energy is supplied to the control box by a lead-in Vcable comprising conductors 82 and ing elemen-ts and electrically operated valves. A

line switch 85 controls the supply of current to aesinet the. machine.- Conductors 85 and 8-1 constitute a shunt heating circuit connected to the

wires

82 and 83 of the power circ-uit, and supply electrical energy through a transformer 88 to the heating elements 35 andL 43 in parallel through wires 80 and 9|. The transformer 88 is of the variable tap type and includes an adjusting knob 32 mounted on the control panel of the machine. The transformer k38 controls the wattage input and consequently the temperature of the heaters 35 and 53. The primary of the transformer 33 is connected to the conductors 815 and 81 by a normally open switch 33. This switch is automatically closed upon closing of the main switch 35 by a relay coil 04 which is connected between

power lines

82 and 83 by the conductor 01 and a conductor 95.

The pressure valve 51 and the exhaust 6.3 are Operated by solenoids 33 and 31 respectively, each valvev being spring retracted to closed position upon the cle-energization of the associated solenoid. The solenoids 03 and 51 are formed with a common terminal connected by lead 98 to the conductor 95 and the power line 82. The other terminal of solenoid 93 is connected to the line 33 by Va shunt circuit comprising the conductors 30, |110, contact switch arm |02, movable between contacts and |03, Iand conductors |06, and |05. The other end of the solenoid01 is connected to the power line 03 by a shunt circuit comprising conductor |05, contact 103, switch arm |02, and conductors |04 and |05.

The pressure valve 54 and the discharge valve 62 for operation of the piston 25 are actuated by solenoids |01 and |08 respectively, each valve being spring retracted -to its closed position. Solenoid |01 is connected to the power line S2 by the conductor |09 and to power line 83 by a shunt circuit comprising the conductor 111 including the micro switch 15, conductor |12, contact H3, switch larm 1|`1 and conductors 115 and |05. Solenoid. |03 is connected to the power line 82 by the common conductor |00 and to line 83 by a shunt circuit comprising conductor |10, con.- tact H0,` switch arm |14, conductor and conductor 105.

'Current flow from anode 13| to cathode |32 of the gas trigger tube |33 occurs upon charging of thegrid |33 to a predetermined value, the resistor |39 limiting current flow from the grid 13B-to cathode |32. The grid is charged with a positive yvoltage to the prescribed value by an -RC voltage accumulator circuit 14 connected between the lcathode `|23 of the rectifier tube |21 and ythe conductor |05. This circuitl .includes `a f valve 33. Energization of filtering circuit 1112 for lteri-ng the same and the circuit of the relay |23. As usual this accumulator circuit comprises resistance and con.- denser elements as shown,L the time intervalrequired for the voltage build-up beingl regulated by the vari-able resistor |43. Discharge of the RC circuit is provided for by a discharge circuit comprising the conductor |43 in which i-s inter- .posed .the usual resistance element |45 having. a contact terminal vUlti adapted to be engaged. by a movable switch arm |41.

When the switch ||8 is closed, thev relay .|23 is energized and moves switch arm |02 into .engagement with contact |01, connecting; conductors |00 and |05 to complete the circuit by which the solenoid is energized for the operation of the valve 51.

Energization of relay |23y also moves the switchA arm |611 out of engagement with the contactA terminal |35 of the resistor |45 to open the discharge circuit 1M and the accumulator circuit be.- gins to charge. Whenl the accumulator circuit-is charged with the predetermined voltage. the grid 133 actuates the trigger tube |33 allowing current to flow from the anode 13| to cathode |32 to energize the relay |29. l

Energization of the relay |23 moves the switch arm |53 out .of engagement with the contact |33 thereby de-energizing relayv coil |23. De-energization of thev relay coil |2-3vcauses the switch arm |02 to be moved into engagement with the con tact 103 to electrically connect conductor |-06With conductor |061 to complete the circuit for enerzigation of solenoid 91 for the operationof the the relay coil# |22 0 also causes switch arm 114 to engagethe'contact` 1 |3130 electrically` connect conductor ||2 with conductor ||51and thus energizethe'solenoid |01- which opens the pressurer valve 55 for the loweringoi the tool operator l5. When the switch H8 is opened the relay |20 is de-energ-ized andl the switch arm |58 again engages contact |39. The de-energization of the relay |20. alsov causes the switch arm |14 tol be moved'. into engagement with contact |10 to-` connect conductor |13'with conductor |15. and 'thus complete; the circuit for energization of the solenoid |08. for opening the discharge valve 62. resulting in the elevationof the tooloperator l5.

The micro switch @5f-is in closed. positionwhen the heater element 13. is in its nlower-most posi# tion and opens at the initiation of theupward movement of this heater in response to opening of the valve 52. The microswitch 55isinterposed on the conductor 111 and prevents operation of the solenoid 101 in response to closing of the switch H3, 111s untiltheheater. |13 has reached the-lower limit of itstravel A. switch operator, which is shown on thepanel 31 'at |53.- operates a normallyclosedswitch |53 interposed in conductor |30y and ay normally closed switch |55 which normallyA short circuits a high resistance element |55 of. the voltageaccumulator circuiti4 1M. The operator` |53fin one position closes the switches |50 and |55 but when the operator 1531sl thrown to its other position, switches |5llfand IE5-are opened, havingthe effect of preventing movement of the tool operatorI 15 and increasing the time interval required to charge the gridy 133;.suiliciently forpassagef of currentafrorn anode |315 to cathodeY 132` of`l the gastrigger tube 133.

Thefmachine of thepresentl inventiorrxis par' ticularly designedv for dimpling. Dural orf other metals which may be .worked-.coldziwithouti themleay velpnnt of' structural weakness. A switch operator mounted on the panel 8|, and indicated in Figure 2 by the numeral |51, operates four switches which appear on the wiring diagram of Figure 3 and are designated by the numerals |58, |59, |5|, and |52. Switch |58 is interposed in conductor 95 and when open prevents energization of the relay coil 94 which controls the heater circuit. Switch |59 has two positions, designated on the diagram as M and D. When this switch is in position M conductor i I 5 is connected to conductor |05 permitting operation of the pressure valve 51 and discharge valve 53. When it is in'lposition D it short-circuits the voltage accumulator discharge circuit |44, connecting this circuit through conductor |63 to conductor |05.

Switch |5| has two positions, indicated by the letters M and D. When in the position M conductors 99 and |00 are'connected completing the circuit for operation or the valve 51. When in position D conductor I|| is connected to conductor through a cross-circuit conductor |64 for energization of solenoid |01 for the operation of pressure valve 54 to lower the tool operator l5.

Switch |02 the letters M position M the plete and the has two positions, designated by and D. When this switch is in circuit for the solenoid 91 is comdischarge Valve 63 may be operated to retract the heating elements to their normal positions. When this switch is in position D it connects conductor H6 with conductor |05 through the cross circuit conductor |05, completing a circuit for the operation of solenoid |90 which actuates discharge valve 52 for the elevation of the tool operator |5.. Y

When the operator |51 is turned to the right handy position designated Dural, switch |58 is opened and the other threeswitohes are in their D position. With the switch |58 open the relay 94 is Cle-energized and the switch 93 is opened so that the heating elements are no longer connected to the

power lines

82 and 83. Movement. of the switch |59 to the D position short circuits the voltage accumulator I4I preventing charg-l ing of the grid |38 of the gas trigger tube |33 thus rendering inoperative thecontrol relay |29.

When the foot pedal switch I|8 is now closed current iows through relay coil |23 which causesl the switch arm |02 to move into engagement with contact I0| to complete a circuit through conductor |09, solenoid |01, conductor ||I, including micro switch 45 now held closed by the heater 43, conductor |64, switch |0I, conductor |00, switch previously explained, energization of the solenoid I 01 actuates the valve 54 to lower the tool operator |5 to bring the tool 34 into engagement with a workpiece not shown in the drawing but placed between the dies 34 and I6. As explained above,. the tool operator is such that it will apply a per-- cussive force to the tool 34 after the tool has. been moved into engagement with the work piece and isapplying a predetermined force against the same.

IUI-|02, and conductors |04 and |05. As: f

I 08 actuates valve 62 to permit the lever I9 to` return the piston to its original position and raise the tool operator I5. The tool 34 as it is connected to the operator I5 moves out of engagement with the work piece and the same may be removed from the machine o1 a newarea presented to the dies of the same. In eithery case the machine is immediately ready for another work operation which may initiated by closing of the foot operated switch H8.

While there have been described herein certain embodiments now preferred, it is to be understood that the invention is not to be confined to the particular embodiments illustrated for it is susceptible to changes in form and detail coming within the scope of the appended claims.

We claim:

1. A sheet metal forming machine comprising: a frame having a work receiving throat and comprising a pair of vertically spaced laterally extending arms; a tool fixed to onev of said arms; tool loperating means; means for mounting said operating meansron the other of said arms for movement toward and away from the fixed'tool; Ia tool carried by said operating means and adapted to be moved by said operating means into working engagement with'a sheet of material disposed in said throat; a lever pivotally mounted intermediate the end thereof tothe arm carrying said operating means; means interconnecting one end of said lever and said operating means; resilient means normally holding said lever in a position in which the tool carried by said operating means is in an inoperative position; means connected to and adapted to move the other end of said lever in one direction whereby the end connected to said operating means moves in the opposite direction to move said operating means and the tool carried thereby into gradual, unimpacted engagement with a sheet of material disposed in said throat; and means made operative upon the application of a predetermined force resulting from the engagement between vthe tool carried by said operating` means and saidsheet for actuating the latter to cause said tool to percussvely impact and angularly 4form said sheet, with planar and rectilinear surfaces that define a dimple for a flushetype rivet, saldresilient means returning said lever to =its normal position after the work operation to permit a ydifferent area of said sheet to be moved into said throat.

2. In a sheet metal forming machine, the rcom-- bination of: a frame providing a work receiving throat `and comprisingan upright and a pair of laterally extending arms on the two sides of said throat respectively; a support carried by the frame for work disposed in said throat; a first formingtool carried by one of said arms; apercussive tool gun carrying .a pneumatically operated, impulse-stroke, second forming tool, said gun being mounted on the other of said arms and reciprocably movable with respect to said support, said seco-nd tool being reciproca'bly operable by said gun in response to a predetermined pressure applied to the metal sheet by said iirst and second tools whenin engagement with said metal sheet; fluid pressure operated means for moving said gun to bring said tool intov progressively increasingpressural engagement with/said sheet, said fluid pressure operated means including a spring retracted, single-acting piston-cylinder means, one element or" which is stationarily 'mounted on said frame and the other element of which is connected to reciprocably move said gun,

said cylinder having associated therewith a pressure inlet passage means and an exhaust passage means and a selector valve means for controlling said passage means; an electric solenoid means for operating said selector valve means; and a manually operated switch for said electric solenoid means.

3. In a sheet metal forming machine, the combination of: a frame providing a work receiving throat and comprising an upright and a pair of laterally extending arms on the two sides of said throat respectively; a support carried by the frame for work disposed in said throat; a first forming tool carried by one of said arms; a percussive tool gun carrying a pneumatically operated, impulse-stroke, second forming tool, said gun being mounted on the other of said arms and reciprocably movable with respect to said support; said second tool being reciprocably operable by said gun in response to a predetermined pressure applied to the metal sheet by said rst and second tools when in engagement withl said metal sheet; fluid pressure operated means for moving said gun to bring said tool into progressively increasing pressural engagement with said sheet, said fluid pressure operated means including a spring retracted, single-acting piston-cylinder means, one element of which is stationarily mounted on said frame andthe other element of which is connected to receiprocably move said gun, said cylinder having associated therewith a pressure inlet passage means and an exhaust passage means and a selector valve means for controlling said passage means; an electric solenoid means for operating said selector valve means; a manually operated switch for said electric solenoid means; and means for returning said moving means to its original position; said percussive means returning with said moving means whereby the tool carried by said percussive means is moved out of engagement with said sheet so that a different area of the same can be presented to said tool.

4. A sheet material forming machine, comprising: a stationary forming tool adapted to support a sheet of material; a movable forming tool; tool operating means carrying said movable tool; means for bodily displacing the tool operating means and the movable tool concurrently to bring the latter into an initial and progressively in creasing localized contact with said sheet; percussive means directly supporting said movable tool and independently movably mounted in said bodily movable tool operating means for movement relative to said stationary forming tool; means responsive to a predetermined amount of pressure between the movable tool and the sheet to effect independent movement of said percussive means; and means for returning the tool operating means to its original position carrying said percussive means and said movable tool.

5. A sheet material forming machine, comprising: a stationary forming tool adapted to engage 'a sheet of material; a, movable forming tool; tool operating means carrying said movable tool; means for bodily displacing the tool operating means and the movable tool concurrently to bring the latter into an initial and progressively increasing localized contact with said sheet; fluid operative percussive means directly engaging said movable tool and independently movably mounted in said bodily movable tool operating means for movement relative to said stationary forming tool; uid pressure means having the one terminal connected to a source of pressure and having the other terminal communicable with said percussive means at a predetermined amount of pressure between said movable tool and said sheet to effect further movement of said independently movable percussive member and urge the toool carried thereby into further and deforming contact with said sheet; and means for returning the movable-tool-carrying tool operating means to its original` position carrying said percussive means and said movable tool.

GEORGE D. RE'CHTON. DELBERT J. WARD. JACK H. WATSON.

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

UNITED STATES PATENTS Number Name Date 2,269,778 Merrill Jan. 13. 1942 2,323,015 Dent June 29, 1943