US3253399A - Impulse forming and like machines - Google Patents

Description

May 31, 1966 F. BAKHTAR ETAL 3,253,399

IMPULSE FORMING AND LIKE MACHINES Filed Nov. 4, 1964 Z Sheets-Sheet l United States Patent 3,253,399 IMPULSE FORMING AND LIKE MACHINES Farhang Baklltar and Stephen Albert Tobias, Birmingham, England, assignors to National Research Development Corporation, London, England, a corporation of Great Britain Filed Nov. 4, 1964, Ser. No. 408,959 Claims priority, application Great Britain, Nov. 5, 1963, 43,728/63, 43,729/63 14 Claims. (Cl. 6016) This invention relates to impulse forming machines, in which term is included forging and like machines. In such machines, a workpiece is impacted by means of a high energy ram or the like so as to be shaped or otherwise worked as required. Considerable interest has arisen in the possibility of deforming material under a rate of strain far exceeding the rates achieved in conventional manufacturing processes and it has been proposed to achieve this mode of deformation by action of a fast-moving ram, which will normally be relatively heavy, the workpiece being deformed to shape, for instance, by reason of the moving ram carrying one part of a die into impulsive cooperation with another part of the die carried by a stationary, or oppositely-moving ram. In known machines, compressed gas, such as nitrogen, is released to propel a piston assembly associated with the ram and thereby to provide at least the principal source of energy for the moving ram(s).

In accordance with the invention, in an impulse forming, forging or like machine, use is made of the energy of combustion of a fuel or other release of chemical energy of a material, to provide at least part of the energy for the initiation of movement and/ or the full movement ice injecting fuel, such as petrol, into the combustion chamber and a vent valve 14 which is used on the return stroke of piston 3 for venting the space in cylinder 4 above the piston, to atmosphere. Three equally spaced tie rods 15 clamp the closure members 5 and 6 to the cylinder 4, closure member 6 being provided with a number of ports 20, each being associated with a relief valve (not shown) which is set to operate at a relatively low pressure.

of the impulsed part of the machine. Thus, in accordance with a feature of the invention, petrol may be ignited in a piston and cylinder arrangement of such a machine and the energy of combustion is imparted to the piston and therefore to the ram. Additionally, compressed gas may be used to assist in causing movement of the ram, or to continue to energise the ram.

In a preferred construction of machine according to the invention, the piston is subject to gaseous pressure, such as front a source of compressed air, on one side and to actuating forces due to release of chemical energy on the other side, the arrangement being such that said gaseous pressure at least is to be overcome before movement of the piston is initiated under said actuating forces. The arrangement may also be such that some energy for the working stroke of the ram can be derived from the source of gaseous pressure.

The invention has the further object of providing a sequence control device for automatic operation of an impulse-forming machine such as has been described above and such as is described in further detail below.

One preferred embodiment of the invention will now be described by way of example with reference to FIG- URE 1 of the accompanying drawings which shows a central section through an impact forging machine. FIGURE 2 is a circuit diagram of control suitable for operating such a machine.

In the drawing, a ram 1 is mounted on the end of a sliding shaft 2 which carries a piston 3 arranged to slide within a cylinder 4. The cylinder 4 has a closure member 5 at the upper end, and a closure member 6 at the other, the shaft 2 sliding in a bearing 7 which has a gaseous seal 8 sufficient to support gaseous pressure in the cylinder 4 beneath the piston 3.

In the upper closure member 5 is formed part of a combustion chamber 9 which is completed by a radiative head carrying an inlet valve 11 and an exhaust valve 12. The closure member 5 also carries an atomiser 13 for The ram 1 carries a tool 16 which co-operates with a lower tool 17 supported in a platen 18, the cylinder 4 and its associated parts being spaced from the platen 18 by means of three equally spaced supports 19.

In operation, taking the sequence. from the situation where the ram 1 is in its impacted position, with the tools 16 and 17 in contact with a workpiece, compressed air at, say 20 to 40 p.s.i. is introduced through one of the ports 20 and the piston 3, together with the attached ram 1, rises in its cylinder, the vent valve 14 and the exhaust valve 12 being open. When the top of the cylinder is reached, the head of the piston 3 seals againnt the underside of closure member 5 under the pressure of air in the cylinder 4 below the piston.

In order to energise the ram 1, a flow of pre-heated air from a supply at, say, -250 p.s.i. is led into the combustion chamber 9 through the inlet valve 11, the exhaust valve 12 being left open for an instant to enable any combustion gases remaining from a previous energising stroke to be scavenged from the chamber. After the exhaust valve 12 has been closed, further air enters through inlet valve 11, pressurises the chamber and, simultaneously, petrol is sprayed into the chamber through the atomiser 13, sufficient time then being allowed for mixing to be complete in virtue of the swirl imparted to the incoming air.

The vent valve 14 is then closed and the petrol/air mixture is sparked off by the sparking plug 21 in the combustion chamber.

Rise of pressure in the chamber due to combustion of the mixture will overcome the back pressure of air in the cylinder 4 below the piston 3; whereupon the piston moves, breaking the seal against the underside of closure member 5, and causing high pressure generated in the combustion chamber to be applied to the full area of the piston thereby causing the piston to accelerate rapidly. The relief valves associated with ports 20 operate to prevent an excessive build up of pressure below the piston due to the energising movement, and in this way the ram 1 is impulsed rapidly to bring the upper tool into contact with the workpiece. By suitable choice of the magnitude of piston/cylinder dimensions, the initial air pressure, the quantity of fuel injected and the setting of the relief valves, the piston can be accelerated to any pro-determined velocity to suit the characteristics of the forming process to be carried out with the tool applied to the ram.

After impact, the ram is returned to its upper position as described, ready for the next impact stroke.

Modifications to the machine described may be made Within the spirit of the invention, as will be understood by those skilled in the art. For example, arrangements may be made for air below the piston 3 in cylinder 4 to be compressed during the downstroke and for this air to be used to supply combustion chamber 9, thus reducing the consumption of compressed air from other sources. Further the machine may be made double ended and firing mechanism provided for both rams, in which case use may possibly be made of the invention described in the specification accompanying co-pending patent application No. 408,931 filed on November 4,

1964 in the United States Patent Office.

or control, as used in FIGURE 1, is added in parenthesis to the letter reference.

In FIGURE 2, a relay IV is provided for actuating the inlet valve (11) of the combustion engine and a relay EV for actuating the exhaust valve (12). Relay V is provided for operating a vent valve (14), for venting the compression cylinder behind the piston which drives the platen. Then operation of the relay BPV controls the back pressure valve to enable the pressure behind the piston to be maintained at the desired value.

For fuel injection into the combustion chamber, a fuel pump is used, the pump being kept running and a relay FR- is arranged to cause operation of the fuel rack relay FPR, normally in the stop position, to set the fuel line for fuel delivery; in order that the delivery shall be substantially uniform for each injection, the actual injection is controlled by microswitches S1 and S2 (the latter having double contacts) which switches respectively close near the commencement of the pumping stroke to operate the fuel rack to inject fuel, and open near the end of the stroke to stop injection of fuel. The actual operation of the contacts of these switches will be described in more detail blow. Operation of contacts SR1 of start relay SR, by manually closing the switch labelled START, is arranged to initiate operation of the device through actuation of the start relay slave SRS by closure of contacts SRS/ 1. A stop relay STR is provided to stop the device by opening of its contacts STR/1 and relay STR is arranged to be energised at some suitable point in the sequence. A ire-start switch, marked as such, is provided to enable the device to resume operation. Relay SC is a spare circuit relay that may be used as required for controlling some other desired operation.

In order to actuate the different parts of the gear in the correct sequence, use is made of a switching device comprising three step-by-step selector switches U51, US2 and USS, such as uni-selectors used for telephony.

Switch US1 has three banks of contacts USl/ 1, US1/2 and US1/ 3, switch US2 has four banks, US2/1, US2/2, US2/3 and US2/4 and switch USS has three banks US3/1, US3/2 and US3/3. Each of these banks comprises 25 contacts uniformly spaced through 360 and these are numbered 0, 1, 2, 3 12, followed by a repeat series numbered 1 12 in each bank; contact is made after the second contact 12 is broken. The first bank of each switch is arranged so that both series of contacts 1 to 11 are connected together and so that contact 11 of the first series is connected to contact 1 of the second series; contact 11 of the second series is connected, through a contact SRS/2/1, SRS/2/2 or SRS/2/3 of the starter relay slave switch, to one line L1 of a power supply P. Contacts SRS/ 2/ 1, SRS/2/2 and SRS/2/3 are normally opened for sequence switching but, for example, at the end of a sequence these contacts will be closed and connection of the first banks of contacts in each selector switch causes the selector switches to be re-set to a zero position ready for the next sequence; contact 12 of the second series is connected direct to line L1. In each second bank of selector switches U51 and US2, the two contacts 11 are connected together and to the line L1. In the other banks of each selector switch, like-numbered contacts are connected together as shown, and are also each connected to one of a row of single-way sockets USl/S, US2/S/ 1, US2/S/2, US3/S/1 or US3/S/2 respectively, appropriately numbered 0 to 12 as indicated for sockets USl/S.

One side of the operating coil for selector switch USI is connected, as is one side of each of the coils for the other selector switches US2 and U83, to line L2 of the power supply and the other side of USl is connected through contacts STR/1 (normally closed), contacts SRS/1 (closed only when the starter relay SR has been energised to operate relay SRS through closure of contacts SR/l) and through contacts IG/ 1 of an impulse generator, to the other line L1 of the power supply. So long as contacts SRS/1 and STR/1 are closed, the coil of switch US1 is energised and de-energised respectively each time the impulse generator contacts IG/1 are closed and opened; and in this way, the moving contact USl/C/ 1 is stepped along its row of contacts USl/l at a rate dependent upon the rate of operation of the impulse generator contacts. The moving contacts US1/Cf2 and US1/C/3 are stepped along their respective banks of contacts USl/Z and US1/3 respectively, in step with movement of the contact USl/C/l. Connection of contact USl/C/ 1 to the commoned contacts of the bank US1/1 during this step-by-step operation, has no effect because contacts SRS/2/1 are open normally at this stage.

It will be noted that after 11 such steps, during which connection is made successively at uniform intervals with the sockets USl/S, connection is made through moving contact US1/C/2 between one side of the operating coil of selector switch US2 and the line L1; and, the other side of US2 being connected with line L2, moving contacts US2/C/1, US2/C/2, US2/C/3 and US2/C/4 of the four contact banks of switch US2 each makes one step. The fact that contact USZ/C/l now makes contact with one of the commoned contacts in bank US2/1 has no effect since contacts SRS/2/2 are open for this operation. Since the contact US1/C/2 immediately moves on to the twelfth contact in bank US1/2, the contacts US2/C/1, US2/C/2 etc. remain on contact number 1 of their respective banks until the next time that the contact US1/C/2 makes contact with the second of the eleventh contacts, in which case it takes another step. Moving contacts US2/C/3 and US2/C/4 being connected together (in fact they may be parts of a double contact arm of the selector switch), it is seen that connection will be made at intervals between like numbered sockets in rows US2/S/1 and US2/S/ 2 and line L1, these intervals being twelve times the interval set by the impulse generator between connection of adjacent sockets in row USl/S to the line L1 through the moving contact US1/C/3.

A similar stepped connection occurs between likenumbered sockets in rows U'S3/S/1 and US3/S/2, though the intervals are 12x12 times the basic interval set by the impulse generator.

It will be seen, therefore, that by connecting, as shown, one side of each of the coils of the operating relays for the different parts of the gear to line L12, and the other side of each to an appropriate socket in row USl/S, the particular coil will be energized each time contact US1/C/3 moves into contact with the associated contact in bank US1/3; if the relays are self-cancelling upon de-energization, then the relay itself will be operated and re-set twice per revolution of contact US1/C/3. If they are not self-cancelling, but rely upon a second energisation of the coil to operate the relay to effect the reverse function, then it may be necessary to link the L2 'side of the coils to another of the sockets in row USl/S so as to provide the second (cancelling) operation of the coil at a suitable interval after the first. To accommodate operation of a large number of parts of gear, it

may be necessary to provide a series of sockets in parallel with each of those in row USl/ S, or alternatively to provide duplicate banks of contacts with moving contacts and associated sockets.

If the intervals afforded by the sweeps of contact US1/C/3 are too small (the maximum interval is be tween contacts 0 and 12 in the bank US1/3 and that is twelve times the basic interval set by operation of the impulse generator contacts IG/1) then recourse can be had to use of sockets US2/S/1 and US2/S/2. As an illustration, operation of the relay coil for vent valve V(l4) will be taken. Thus, by provision of a jumper J1 between a socket V/S/l connected to the appropriate side of the relay coil and a socket in row US2/S/2, and a jumper J2 between the equivalent socket in row US2/S/1 and a selected socket in row USl/S, provision can be made for a greater time interval. By plugging jumper J1 into one of the sockets in row US3/S/2 and jumper J2 into the equivalent socket of row US3/S/1, provision may be made for an even greater time interval.

It -will be seen that, in the latter case by leaving jumper J2 in association with the sockets in row USl/S and USZ/S/l and by inserting a third jumper between the appropriate sockets in rows US2/S/2 and USS/S/l, a finer control of timing is obtainable. Thus if the impulse generator. is set to operate at, say one-tenth second intervals, sockets in row USl/S are energised at one-tenth second intervals, sockets inrows US2/S/1 and US2/S/2 at roughly unit intervals and sockets in rows US3/S/1 and US3/S/2 at roughly ten second intervals. In fact the intervals for the respective steps are one-tenth second, 1.1 seconds and 12.1 seconds.

As an example of the use of the switching device to open the vent valve, say 4.3 seconds after the starting switch has been operated, and to close it after 32.8 seconds, the jumper I la connects sockets V/S/l to the socket numbered 3 in row US2/S/1 and jumper J2 connects the equivalent socket in row US2/S/2 to socket numbered 7 in row USl/S, these giving delay times of 3.5 seconds and. 0.7 second respectively, which totals 4.3 seconds; and jumper J3 connects socket V/S/2 to the socket numbered 2 (equivalent to 24.2 seconds elapsing) in row US3/S/2; jumper J4 connects the equivalent socket in row US3/S/1 to the socket numbered 7 (equivalent to a further 7.7 seconds elapsing) in row US2/S/3 and jumper J5 connects the equivalent socket in row USZ/S/l to the socket numbered 9 (equivalent to a still further 0.9 second elapsing--giving a total of 32.8 seconds) in row USl/S. The vent valve solenoid is then pulsed to be energised after 4.3 seconds and further pulsed to be de-energised after the requisite interval.

Connections for each of the other relays for operating parts of the gear will be evident from the above description and from the diagram of connections shown in the drawing. If necessary more than one contact may be in elfect plugged into a single socket by using plug contacts, that may plug into the back of another or alternatively further rows of sockets may be provided these being parallelled with the appropriate sockets in the existing rows.

The circuit for ensuring injection of he correct amount of fuel at the right part of the sequence however, probably needs further detailed description. Relay PR is a pulse-operated relay and pulsing upon energization by the sequence switch results in closing of the slave contacts FR/l. At a suitable point in the pumping cycle of the fuel injection pump, the micro-switch S1 is closed by cam-operation from the pump shaft, thereby completing the operating circuit of pulsing relay R1, thus resulting in closure of its slave contacts Rl/l. Closure of slave contacts R1/1 causes operation of relay R2, the contacts R2/1, R2/ 2 and R2/ 3 of which thereupon close. Closure of contacts R2/1 completes the solenoid FPR circuit and actuates the fuel pump rack. to the pre-set injection position, thus causing injection of the fuel. At a later stage in the rotation of the fuel injection pump, contacts 82/1 and 82/2 of the further micro-switch are closed and relays R1 and FR are thereupon pulsed to reset them and to result in relay R2 being de-energised to stop injection of fuel, the fuel injection circuit then being reset for further operation.

We claim:

1. An impuse forming machine for automatic operation and having at least one impulsed part, a piston associated with said impulsed part, a cylinder for said piston, an

energy chamber associated with said cylinder, the opening from said energy chamber into said cylinder being of substantially smaller cross sectional area than the opera-.

tive area of the said piston, at least one orifice in said chamber for the introduction of a combustible component for impulsing said piston, means for exhausting gases from said energy chamber, at least one vent in said cylinder towards the opposite end thereof to said energy chamber, pressure relief means associated with said vent and means for leading pressurized gas to said opposite end of said cylinder to force said piston into a sealing position against said energy chamber opening.

2. An impulse forming machine as in claim 1 comprising venting' means in said cylinder for venting the space between said piston and said energy chamber during travel of said piston towards said energy chamber opening.

3. An impulse forming machine as claimed in claim ll, means for introducing compressed gas to the said chamber to move said piston and in consequence said impulsed part towards said chamber so that said piston may seal said chamber, means for metering said supply of comfoustible compound to said chamber and means for initiating combustion of said supply of combustible compound.

4. An impulse forming machine as claimed in claim 3, wherein a sequence control is provided for operation of controls for each of said means in pre-arranged sequence.

5. An impulse forming machine as claimed in claim 4, wherein each said means is provided with electromagnetic actuating mechanism and said sequence control comprises a plurality of step-by-step selector switches with contacts of which are associated connecting members, the first selector switch being arranged so that its contacts can be swept repeatedly at constant intervals and the second and subsequent selector switches being arranged so that their contacts can be swept in turn after a selected number of contacts of the previous selector switch have been swept,

and connecting means associated with each said electromagnetic actuating mechanism whereby connections may be made between said connecting means and selected individual connecting members to enable actuating circuits for said mechanisms to be completed in a given sequence.

6. An impulse forming machine as claimed in claim 5, wherein jumping connectors are provided for selective connections between said connecting members and said connecting means.

7. An impulse forming machine as claimed in claim 6, wherein said connecting members and said connecting means comprise socket means and said jumping connectors are provided with plug means for engaging said socket means as selected.

8. An impulse forming machine as claimed in claim 5, wherein a plurality of said connecting members is associated with each contact of at least one of said selector switches.

9. An impulse forming machine as claimed in claim 5, comprising an impulse generator for energising said first selector switch to cause its contacts to be swept at a controlled rate.

10. An impulse forming machine having at least one impulsed part, at least one piston and cylinder arrangement of which the piston is associated with said impulsed part, an energy chamber, means for supplying a combustible chemical compound into said chamber, means for introducing combustion gas into said chamber, means for venting said chamber, means for introducing compressed gas to the said chamber to move said piston and in consequence said impulsed part towards said chamber so that said piston may seal said chamber, means for metering said supply of combustible compound to said chamber and means for initiating combustion of said supply of combustible compound, wherein a sequence control is provided for operation of controls for each of said means in pre-arranged sequence, and wherein each of said means is provided with electromagnetic actuating mechanism and said sequence control comprises a plurality of step-by-step selector switches with contacts of which are associated connecting members, the first selector switch being arranged so that its contacts can be swept repeatedly at constant intervals and the second and subsequent selector switches being arranged so that their contacts can be swept in turn after a selected number of contacts of the previous selector switch have been swept, and connecting means associated with each said electromagnetic actuating mechanism whereby connections may be made between said connecting means and selected individual connecting members to enable actuating circuits for said mechanisms to be completed in a given sequence.

11. An impulse forming machine as claimed in claim 16 wherein jumping connectors are provided for selective connections between said connecting members and said connecting means.

12. An impulse forming machine as claimed in claim 11 wherein said connecting members and said connecting means comprise socket means and said jumping connectors are provided with plug means for engaging said socket means as selected.

13. An impulse forming machine as claimed in claim 10 wherein a plurality of said connecting members is associated with each contact of at least one of said selector switches.

14. An impulse forming machine as claimed in claim 10 comprising an impulse generator for energizing said first selector switch to cause its contacts to be swept at a controlled rate.

References Cited by the Examiner UNITED STATES PATENTS 2,132,148 10/1938 Davis 6026.1 X 2,160,218 5/1939 Kingston et a1 60l6 X 2,402,920 6/1946 Seibold 6016 EDGAR W. GEOGHEGAN, Primary Examiner.

Claims (1)

1. AN IMPUSE FORMING MACHINE FOR AUTOMATIC OPERATION AND HAVING AT LEAST ONE IMPULSED PART, A PISTON ASSOCIATED WITH SAID IMPULSED PART, A CYLINDER FOR SAID PISTON, AN ENERGY CHAMBER ASSOCIATED WITH SAID CYLINDER, THE OPENING FROM SAID ENERGY CHAMBER INTO SAID CYLINDER BEING OF SUBSTANTIALLY SMALLER CROSS SECTIONAL AREA THAN THE OPERATIVE AREA OF THE SAID PISTON, AT LEAST ONE ORIFICE IN SAID CHAMBER FOR THE INTRODUCTION OF A COMBUSTIBLE COMPONENT FOR IMPULSING SAID PISTON, MEANS FOR EXHAUSTING GASES FROM SAID ENERGY CHAMBER, AT LEAST ONE VENT IN SAID CYLINDER TOWARDS THE OPPOSITE END THEREOF TO SAID ENERGY CHAMBER, PRESSURE RELIEF MEANS ASSOCIATED WITH SAID VENT AND MEANS FOR LEADING PRESSURIZED GAS TO SAID OPPOSITE END OF SAID CYLINDER TO FORCE SAID PISTON INTO A SEALING POSITION AGAINST SAID ENERGY CHAMBER OPENING.

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