JPS6253306B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The invention disclosed and claimed herein generally relates to control techniques and apparatus for operating transfer machines with improved efficiency. More specifically, the present invention enables each machining unit of the transfer machine to be activated only when each part (i.e., workpiece) is present at its respective machining station. The present invention relates to a transfer machine control device that allows each unit to perform its own machining operation.More particularly, the present invention provides a control device of the type described above that controls shift registers in synchronization with the movement of parts passing through the machine. The present invention relates to monitoring the movement of parts through a transfer machine by shifting digital data bits through the transfer machine.

As is well known in various manufacturing operations, a transfer machine is a machine or machine that is configured to receive workpieces or parts one after the other and performs a series of separate machining operations on each part. It is a processing system. During each part transfer cycle in a series of part transfer cycles, a transfer mechanism operates to move the part from the input station to the first processing station in the series and to the last processing station in the series. The part is moved from the processing station to the output station, and each other part in the machine is advanced one processing station in the series of processing stations. After each transfer cycle, the transfer
The machine begins a machining unit cycle during which the part advanced by the transport mechanism is subjected to one of the individual machining operations by the machining units at each machining station.

Transfer machines of the above type find wide application in the machining of metal parts, especially when large part quantities are required. By placing an axially driven cutting tool at each processing station and providing an electronic control to directly actuate the cutting tool and the transfer mechanism, transfer machines can process successive parts in a relatively short period of time. Multiple machining steps can be automatically applied to each part in the process. However, if for some reason a part fails to enter the machine during a part transfer cycle, the operating efficiency of the transfer machine can be significantly reduced. In the event of such a failure, automatic and continuous operation of the transfer machine is terminated. In this case the machine is
It can only be actuated manually or by operator intervention. However, with this kind of operation,
This can create gaps in the flow of parts moving through the sequence of processing stations. The creation of this gap, in turn, causes unnecessary wear on the processing unit as the unit may perform a work cycle or start up when a part is not present at its processing station.

Additionally, if a processing unit performs a work cycle when a part is not at its processing station, the time required to machine a series of parts increases unnecessarily. Since machining units generally require different amounts of time, or cycle times, to perform their respective machining operations, the time between two consecutive part transfer cycles is the longest such cycle time. It is easy to see that it is more than that. If the unit with the longest cycle time is activated when no parts are present at its processing station, it will take longer than necessary before the next transfer cycle can begin.

Through the present invention, the applicant has discovered that transfer
This allows the transfer machine to continue operating even if there is an intermittent failure in the delivery of parts into the machine. Furthermore, the present invention limits the time between part transfer cycles to within the longest cycle time of the unit in which the part actually exists, and allows the processing unit to follow the part transfer cycle and perform a cycle as long as the part is in the unit. It is something that can be adjusted.

The present invention can be implemented with relatively simple modifications to conventional transfer machine control equipment. However, the scope of the present invention is in no way limited thereby.

In the present invention, a loading station is provided to receive parts within at least some part receiving time of a series of part receiving times, and a plurality of selectively placed stations are provided to perform predetermined machining operations on the received parts. A transfer machine apparatus having a processing unit is provided. A transfer device is provided for moving a given one of the received parts from the incoming station towards each of the processing units in a predetermined order, so that the given received part is divided into a series of parts. During a transfer cycle, a part is moved from one of the processing units to another of the processing units. During each part transfer time, a digital code storage device receives a digital code, and if a part is received at the loading station during the part transfer time, the storage device receives the first digital code and stores the part during the part transfer time. If the second digital code is not accepted by the loading station, the storage device receives the second digital code. The storage device is provided with a number of individual digital code storage locations, with each processing unit having a unique, one-to-one correspondence with one of the storage locations. The digital code synchronously associated with the movement of the received parts and thus received in the storage device at the end of a selected number of part transfer cycles is shifted by a shifting device to move the received parts into place. The digital codes contained in a given memory location each contain a first or a second digital code, depending on whether or not they are present in the processing unit corresponding to a given memory location. A selection actuator responsive to the contents of each memory location causes a first digital code to be activated at the end of a selected number of part transfer cycles if the first digital code is contained in a given memory location. The processing unit corresponding to a given storage location can perform the predetermined processing operation, otherwise the processing unit is prohibited or prevented from performing the predetermined processing operation.

Preferably, the digital code storage in the device includes a shift register with a number of locations for storing individual digital bits, each bit storage location containing one of the digital code storage locations. It is desirable to do so. each of the first digital codes includes a first logic level digital bit, such as a logic one bit;
Each of the second digital codes includes a second logic level digital bit, such as a logic 0 bit. Preferably, the shifting device also includes means for shifting a given digital bit from a first bit storage location to a second bit storage location during a component transfer cycle. Here, the processing unit corresponding to the first memory location precedes the processing unit corresponding to the second memory location in the aforementioned order of processing units.

In a preferred embodiment of the invention, each machining unit includes a shaft-driven tool for performing a predetermined cutting operation on a metal component. The transfer apparatus for this type of embodiment includes, during each part transfer cycle, moving received parts from an input station to a first processing unit in the sequence of processing units and transporting received parts from the last processing unit in the sequence. A moving bar structure is included which is operable to move the parts to the output station and advance each other received part by one processing unit in the sequence of processing units. The preferred embodiment also activates the processing unit after a part transfer cycle depending on whether the bit storage location corresponding to the processing station after the transfer cycle contains a first or second logic level digital bit. Or a device for pausing is included in the selective actuation device.

Alternatively, the present invention provides that if a part is received at an input station of a transfer machine during a given part receiving time, the first digital placing a bit into a shift register and, if no part is received at the loading station during a given part receiving time, placing a second digital bit into the shift register during the given part receiving time; moving one of the received parts in a predetermined order to each of a number of processing stations provided within the transfer machine; creating a one-to-one correspondence between each of the plurality of bit storage locations;
shifting the first and second digital bits in the shift register to respective processing stations of the transfer machine in synchronous relationship with the movement of the received part; activating a given processing station at a given time to perform a predetermined processing operation on the received part, if the bit storage location corresponding to the processing station contains a first digital bit; and inhibiting or preventing activation of the given processing station at the given time if the bit storage location corresponding to the given processing station at the given time contains a second digital bit. It can also be seen as a method of controlling the operation of a transfer machine consisting of

SUMMARY OF THE INVENTION It is an object of the present invention to provide a transfer machine in which transfer operations or cycles occur even when no parts or workpieces are present at the input station of the transfer machine.

Another object of the invention is to provide a transfer machine of the above type in which a machining unit of a transfer machine is activated and a predetermined machining operation is carried out during a machining unit cycle as long as a part is present in the machining unit during the machining cycle. Our goal is to provide transfer machines.

Yet another object of the invention is to provide a transfer machine of the above type in which the length of the machining unit cycle is limited to the time required for all machining units in which each part is present to complete its respective machining operation. It is about providing.

Yet another object of the invention is to provide an electronic control device for controlling the operation of a transfer machine of the type described above.

Yet another object of the invention is to activate or prevent activation of each machining unit of a transfer machine during a machining cycle according to digital data stored in a shift register at the beginning of the machining cycle. An object of the present invention is to provide an electronic control device for a transfer machine.

These and other objects of the present invention will become more readily apparent by studying the following specification in conjunction with the drawings.

FIG. 1 will be explained. The figure shows metal parts 1
2 shows a transfer machine 10 arranged to receive a flow of 2 and perform N types of processing operations on each received part according to a predetermined order. Transfer machine 10 is equipped with a transfer bar or other part advancing structure 14 and is further provided with a transfer bar drive mechanism 16 for operating the transfer bar in successive part transfer cycles. In this case, the transfer device consists of a structure 14 and a drive mechanism 16. Furthermore, the transfer machine 10 is equipped with an input station 18, an output station 20, and N types of processing units 22. Each machining unit 22 performs one of the machining operations described above during a machining unit cycle;
It is located at one of N processing stations. The processing units are respectively arranged at the processing stations so that when the part 12 is continuously moved from the processing station 1 to the processing station N, N types of processing operations are performed on the part 12 in the above-described predetermined order. .

Each processing unit 22 includes a fixture 24 and a main shaft 2.
6 and a spindle head 28. A fixture 24 is provided to selectively hold the component 12, and a spindle 26 is provided to drive a cutting tool, such as a tool for milling, boring, or other conventional metal cutting operations. The spindle head 28 of the machining unit 22 is movable relative to the part 12 held in the fixture of the machining unit, allowing for controlled feeding of a tool 30 into the held part. Processing unit 22 as well as other components of transfer machine 10
It should be understood that the specific shape of the transfer machine also depends on the application of the transfer machine. Accordingly, FIG. 1 depicts each component of transfer machine 10 in a highly simplified and generalized manner.

FIG. 1 will be further explained. The figure shows a controller 32, such as a programmable electronic controller, coupled to each of the components of transfer machine 10.
shows. The control device 32 is the transfer machine 1
The transfer machine is configured to operate the respective components of 0 in synchronous relation to each other, thus causing the transfer machine to continue alternating part transfer and processing unit cycles. Further, as explained below, controller 32 is configured to operate the respective components of the transfer machine in accordance with the present invention.

At the beginning of a part transfer cycle, the transfer bar drive mechanism 16 is directed by the controller 32 to lift the transfer bar 14 upwardly. This results in bar 14
is engaged with all parts 12 present in the processing unit 22 or loading station 18. The bar 14 then moves forward, so that the parts in the transport station 18 are transferred to the processing unit in the processing station 1, the parts in the processing unit in the station N are transferred to the unloading station 20, and the parts in the processing unit in the processing station m are transferred to the processing unit in the processing station m. A part is moved to a unit at processing station m+1. Here m<N. then bar 1
4 is lowered and then returned to its original position,
Finish the parts transfer cycle.

After the part transfer cycle is completed, controller 32 executes the processing unit cycle. During a machining cycle, all machining units 22 on which part 12 resides are activated and feed their tools 30 into the part at a controlled feed rate. Machining unit tool 30
is fed to a predetermined depth according to the machining operation to be performed by this unit.
When all activated machining units have reached their respective depths, their spindles and tools are returned to their original positions where controller 32 performs another part transfer cycle. The controller 32 is configured to limit the duration of the machining cycle to the time required by the activated machining units to complete their respective tasks.

After each part transfer cycle, during part receiving time, the transfer station 18 becomes positioned to receive parts for a subsequent part transfer cycle. During the part receiving period, the controller 32 is responsive to both the receipt and non-receipt of parts at the transfer station 18. After the transfer cycle, any parts present at the unloading station 20 are removed therefrom.

FIG. 2 will be explained. The figure shows a programmable controller 32 of the type currently used to control transfer machines or other processing systems and which can be adapted to operate transfer machine 10 in accordance with the present invention. .
This type of control device 32 includes a processor 34 coupled to a power supply 36, a programming keyboard 38, and an input/output section 40. Keyboard 38 is used to enter a set of instructions into processor 34, thereby causing controller 32 to:
As the transfer machine receives and processes a series of parts 12, it becomes configured to perform a defined sequence of logical operations. Depending on the result of each logical operation, a control signal is sent to the input/output section 4.
0 to the transfer machine 10 and also creates the conditions for logical operations thereon. Other conditions for logical operations are determined by signals coupled from the transfer machine to processor 34 via input/output section 40. Such input signals indicate the state or condition of each component of the transfer machine at various times during successive transfer and processing cycles.

The controller 32 includes a controller, such as a Modicon 584, which receives commands in the form of a series of ladder diagrams. As is well known in the art, a ladder diagram is a graphical representation of some logical operations performed by a controller to generate control signals that operate transfer machine 10 in a particular manner. A ladder diagram has a number of horizontal lines known as rungs, each rung containing one or more logic elements or relay contacts. Each contact indicates the status of a transfer machine component, and the contacts are shown open or closed in a ladder diagram to indicate the normal status of the transfer machine during operation. In addition to relay contacts, the rungs of the ladder diagram may be provided with function boxes such as timers or registers.

In a ladder diagram, power can only flow from left to right along the rungs. Therefore,
The coil located at the right end of the crosspiece is activated when all of the crosspiece contacts are in the closed state at the same time. Alternatively, when a vertical path is provided between a coil rung and an adjacent rung, the coil is activated to create a power flow path that includes various rung segments.
Power can flow either upwardly or downwardly through such vertical paths. It will be apparent that the various conditions indicated by the relay contacts in the ladder diagram will continually change as the transfer machine 10 is operated through each successive part transfer and processing unit cycle. The controller 32 therefore repeatedly scans each relay contact in the ladder diagram over very short intervals. If one or more of the conditions that define activation or deactivation of the coil change, the state of the coil changes appropriately during just the next scan. Thus, when a set of conditions defining a particular control signal is generated within the transfer machine, the control signal is immediately generated by the controller and coupled to the transfer machine.

A common convention in ladder diagrams is to indicate open contacts by two vertical, spaced, parallel lines and to indicate closed contacts by vertical, spaced lines connected by diagonal lines. It is to display. A coil whose contacts are closed for only one scan upon activation of the coil to which it is coupled can be indicated by placing an upwardly pointing arrow between two spaced vertical lines. As an additional restriction, if activation of the coil couples a control signal outside the controller 32, the coil may be indicated by a circle placed at the right end of the crosspiece. On the other hand, by starting the coil,
When only further logical operation conditions are provided within the control device, the coils are displayed as rectangles.

A number of well-known or conventional instructions are provided in a ladder diagram format for operating each component of transfer machine 10 while the transfer machine performs each successive part transfer and processing unit cycle. It is entered into the control device 32 via the keyboard 38. One conventional ladder diagram of this type is an interlock circuit, which generates a signal that is coupled simultaneously to each processing unit 22, ensuring their uniform operation.
Interlock circuits of this type, as well as many other conventional ladder diagrams included in the control unit 32, do not have their respective standard form modified by the present invention and are therefore not described herein. I will not elaborate on this. However, some of the other ladder diagrams that may be included in the controller 32 are probably not conventional and will be described herein in connection with FIGS. 3-5. A number of other ladder diagrams, which are basically conventional in the art, but which require modification in view of the present invention, will be described in connection with Figures 6 to 10. .

FIG. 3 will be explained. In the figure, the shift register 42 is connected to each crosspiece 44, 46, 48, 50, 5.
Fig. 2 shows a ladder diagram connected to 2,54. Third
Reference numerals 42a through 42d in the figures are used to indicate how each rung interacts with register 42, shifts data therein, and places data therein. Shift register 42 effectively encompasses one of the aforementioned functional boxes of controller 32 and provides N consecutive locations for storing digital data bits. A particular digital data bit is transferred to shift register 4 during a particular part transfer time.
2, and if the data in shift register 42 is shifted or rotated in response to each part transfer time, a particular data bit may be The nth bit storage location is reached after n transfer cycles. Additionally, if the component 12 is received at the loading station 18 during a specific component receiving time,
Such a part is present at the nth processing station after the nth transfer cycle.

From the above relationships, during the parts transfer time, the parts 12
is received by transfer machine 10 and a logic 1 data bit is placed in shift register 42, and when no part 12 is received during part transfer time and a logic 0 is placed in the register.
If the registers are shifted once in response to each transfer cycle, the data contained in shift registers 42 may be transferred to parts 12 in each of processing units 22 of transfer machine 10 at any given time. indicates the presence or absence of. Each crosspiece 44,
By judicious selection of contacts included in 46 and 48,
Shift register 42 may be operated in accordance with the requirements set forth above.

FIG. 3 will be further explained. The figure shows the crosspiece 48.
The loading terminal of the shift register 42 is shown coupled to the right end of the frame 48, and the crosspiece 48 is provided with a contact 48a. Contact 48a is closed by a component presence signal received from a detection device for detecting the presence or absence of a component as a workpiece at loading station 18, whereupon a logic 1 is coupled to the load terminal of register 42. be done. Contact 48a remains open if no part is present at the loading station;
A logic zero is coupled to the load terminal of register 42. Activation of contact 48a is synchronized with the presence or absence of parts received at transfer station 18 during successive part transfer times and with periodic shifts of register 42. A shift or clock terminal of the register is coupled to a rung 46 which is interconnected with rung 44 via a vertical path for shifting or cycling the data within the shift register 42 in response to each part transfer cycle. Here, the shifting device includes elements 46a and 46 of the crosspiece 46.
Consists of b. The crosspiece 44 includes a "forward transfer" contact 44a that is closed when the transfer bar 14 is advanced during a transfer cycle, and a "transfer bar return" contact 44b that is closed when the transfer bar 14 is returned prior to the start of the transfer cycle. Prepare. Thus, coil 44d is activated when a transfer cycle is initiated and each part 12 within transfer machine 10 is shifted by one processing station. Coil 44d is used for contacts 46a, 46b in crosspiece 46 so that register 42 is shifted by the very next scan following the start of a transfer cycle.

FIG. 3 will be explained once again. The figure shows shift register 42 coupled to crosspieces 52,54. The crosspiece 52 is provided with an "all parts present" push button contact 52a, and the crosspiece 54 is provided with a "control power" contact 54a. By providing the crosspiece 52, even if a part is removed from the processing station of the transfer machine 10 for any reason, the processing station will be returned to the processing station if the part is not present at the processing station after multiple transfer cycles. If the part is returned, further processing can be performed on the part. When the "All Parts Present" pushbutton is pressed, contact 52a closes and a logic one data bit is placed into all N bit storage locations of register 42. The movement of the returned part to a subsequent processing station for completion of processing by transfer machine 10 is then effected by a logic 1 data bit in the shift register. Runway 52 is also used to place a part directly into one of the processing stations of transfer machine 10 without first placing the part at input station 18.

FIG. 4 will be explained. This figure shows a ladder diagram used to provide alerts when shift register 42 malfunctions. The ladder diagram of FIG. 4 includes interconnected rungs 56, 58, and 60 as shown, with rung 56 at contact point 56a.
56e, and the crosspiece 58 includes a contact 58a. Contact 56a is generally connected to transfer machine 1.
0 is in operation, but shift register 4
If there is a logical 1 in the Nth bit memory location of 2, it is opened at the end of the part transfer cycle. Contact 56b is normally open during transfer machine operation. However, if a limit switch located at processing station N senses that a part is present at processing station N at the end of the transfer cycle, a signal is sent to controller 32 via input/output section 40. coupled, closing contact 56b. Since the contacts 56c and 56d are closed when the transfer bar 14 is advanced and lowered, respectively, the closing of the contacts 56c and 56d indicates that a transfer cycle has occurred. The "start/return" control contact 56e is normally in a closed state.

From the above logic condition determined by the crosspiece 56, the coil 56f coupled to the right end of the crosspiece 56 is at logic 0 at the same time that the part 12 is present at the processing station N.
It will be clear that it will only be activated if the data bit is contained in the Nth memory location of shift register 42. The occurrence of such a condition simultaneously causes register 42 to be
Displays faults during operation. As a result, coil 5
Activation of 6f couples a signal to transfer machine 10 to illuminate the shift register fault indicator light. Thereby, processing station N
A warning is given to the transfer machine operator that the parts located in the machine cannot be machined properly. If a logic zero is shifted through shift register 42 simultaneously with the movement of parts through the transfer machine, the various machining units will perform their respective machining operations even though these parts are at their machining stations. It is never activated for execution.

Activation of the coil 56f also occurs at each contact point 5 of the crosspiece 56.
Used in conjunction with contact 58a in shunt crosspiece 58 of 6a to 56d. Activation of coil 56f is maintained regardless of which of contacts 56a-56d is opened until "start/reset" control contact 56e is thereby actuated. The rungs 60 in the ladder diagram of FIG. 4, which do not include any contacts, indicate the flow of power to the controller 32.

FIG. 5 will be explained. In the figure, the coil 62
FIG. 3A shows a ladder diagram with an upper rung 62 and a lower rung 64 coupled to a, and a number of middle rungs, each middle rung including a number of contacts. Contact point 64 of lower crosspiece 64
As in a, each of the contacts on the middle crosspiece is connected by a vertical path between the upper crosspiece 62 and the lower crosspiece 64, so when one of the contacts closes, a path is created for power to flow, and the coil 62a is activated. Contact 66a closes when a signal is coupled to controller 32 to indicate that no part is present at input station 18, and the nth processing station contact
Closed by the presence of a logic 1 in the nth bit memory location of register 42. Therefore, coil 6
2a, the transfer machine 10
The presence of one or more parts within is displayed.

FIG. 6 will be explained. The figure shows that all the components of the transfer machine 10 are automatic.
Moreover, the cross-pieces 68, 70 are shown interconnected to activate the coil 68i when the shift register 42 is operating without failure or error. Crosspiece 68
Contact 68a closes when all of the components of transfer machine 10 operate in an automatic manner, and contact 68b closes when no emergency exists within transfer machine 10. Contact 68c remains closed unless transfer bar 14 malfunctions, and contact 68d remains closed unless there is a shift register failure. Contact 68e is a reset pushbutton contact and contact 68f is actuated by a pushbutton for selecting the automatic mode of transfer machine operation. After such a scheme is selected, coil 68i is activated where a signal is coupled to the automatic scheme indicator light. Activation of coil 68i is also used as contact 70a of crosspiece 70, which closes pushbutton contact 68f after transfer machine operation has begun. Contact 68g is closed to indicate that the main shaft of each processing unit 22 is operating, and contact 68h is closed to indicate that the main shaft of each processing unit 22 is operating.
Closes when the machine is not operated in manual mode.

FIG. 6 will be further explained. In the figure, the crosspiece 72
78, the activation of coil 72e of crosspiece 72 is defined by contacts 72a, 72d, 76a, 76b, with activation of coil 72 indicating the beginning of a part transfer cycle. Contact 72a closes when the selection switch is actuated to place the transfer machine 10 in continuous operation mode, and contact 72d closes when the transfer machine 10 is in continuous operation mode.
Closes when the machine is ready or ready for a transfer cycle. Contact 76a is closed to indicate that the loading station structure used to place parts on the loading station in preparation for a part transfer cycle is retracted and does not interfere with the movement of transfer bar 14. The contact 76b is connected to the coil 62 in FIG.
a is closed and indicates the presence of one or more parts at either the input station 18 or one of the processing stations of the transfer machine 10. By providing contact 76b, a part transfer cycle occurs when even one part is submitted to the transfer machine for processing. However, if there are no parts to be machined, the transfer machine will not perform a part transfer cycle. Here, the transfer initiation device consists of elements 72, 76.

When the coil 72e is activated, the contacts 72c, 7
8a closes, thereby creating a shunt across crosspiece 76. As the parts transfer cycle progresses,
When the transfer bar 14 moves forward, the contact 72b opens,
Contact 74a opens when the transfer bar is lowered, thereby terminating the part transfer cycle.

7 through 9 show that the nth processing unit 2, which is contained within the controller 32 and is located at the nth processing station, during successive processing unit cycles.
This is a ladder diagram that instructs the operation of step 2. The ladder diagram in FIG. 7 will be explained. The diagram shows the interconnected bars 80, 82 in order to define the conditions for activation of the coil 80d, whereby the control of the nth processing unit is placed in the "closed" state. To start coil 80d, the start/reset control must be activated to close contact 80a and keep contact 80b closed to indicate that the unit is not overloaded.
Furthermore, contact 80c must be closed by actuation of a master control relay, which is normally included in controller 32. When coil 80d is activated, contact 82a on crosspiece 82 closes and start/reset contact 80
a is shunted. After unit control begins, when contact 82b is closed by actuation of the automatic/manual selection switch, automatic/manual control coil 82c is activated.

The ladder diagram in FIG. 7 will be further explained.
The diagram shows the bars 84, 86, 88 interconnected to define the conditions for activating the coil 84e, ie, activating the spindle 26 of the n-th processing unit. Contact 84a of crosspiece 84 is closed by a "spindle start" pushbutton, and contact 84b is closed by a selection switch to deselect automatic mode of operation. Contact 84c is closed by a signal from the interlock circuit described above, and contact 84c
4d is closed by activation of coil 82c.

Contacts 84a, 84b are shunted by crosspieces 86, 88, and contact 86a of crosspiece 86 is closed by a "spindle start" signal coupled thereto from an interlock circuit. The contact point 88a is normally connected to each main shaft 26.
Contact 88b is closed when coil 84e is activated. The power flow path is determined when (1) the interlock circuit of the controller 32 indicates that the spindle must be closed, or the spindle is not in automatic mode and the manual pushbutton is operated; (2) It can be seen that coil 84e is activated and is generated through crosspiece 88 only when the main shaft is actually shown to be closed.

The crosspiece 90 shown in FIG. 7 will be explained. The same crosspiece is connected to the tool 3 of the previous n-th processing unit facing the part 12 clamped to the fixture 24 of the n-th processing unit.
The conditions for activating coil 90e indicating partial advance of 0 are shown. To start moving forward, contact 9
0a must be closed to indicate that the fixture is in the clamped condition, and there must be no critical condition. Furthermore, the coil 82c is connected to the contact 90b.
The stay contact 90c must be kept closed by not activating the coil 98c, which will be described later.
Finally, in order to close contact 90d, a logic 1 data bit must be included in the nth memory location of shift register 42 in accordance with the present invention. The nth bit memory location contains a logical 0;
Contact 90d remains open and coil 90 remains open during the part processing cycle about to begin, indicating the absence of a part at the processing station.
e is not activated and the tool 30 of the nth machining unit is not advanced. Here, the portion of the selective actuation device related to the n-th processing unit consists of a crosspiece 90 including a contact point 90d.

FIG. 8 will be explained. This figure shows the use of rungs 92, 94, 96 to control the rapid advancement of the tool 30 of the nth machining unit and also to control the feed of the tool to the part clamped to the fixture of that unit.
shows an interconnected ladder diagram. The tools are
It advances rapidly as it passes through the air gap between the original position of the tool and the clamped part. To rapidly advance the tool and then apply the feed, one of contacts 94a-94e must close, otherwise contact 92
a, 92b must be closed. Contact 92a
is closed by actuating the "Unit Advance" pushbutton and contact 92b is closed by the automatic selection switch contact. Contact 92c must also be closed by activation of coil 90e. If the above conditions are satisfied and the tool 30 of the nth processing unit is initially in the return position, the rapid advance coil 92f
A power flow path is created.

When coil 92f is activated, contact 92e is closed. When contact 92d is also closed by a signal received from the rapid advance starter, contact 94
f is shunted. Therefore, activation of coil 92f is maintained while tool 30 of the nth machining unit is moved from its return position.

In order to further sustain the activation of coil 92f as well as coil 96c, contacts 94a to 9 of crosspiece 94
4e is provided to shunt contacts 92a-92b. Contact 94a is closed by a signal from the controller interlock circuit indicating that all of the units must be present in the machining cycle, and contact 94b is closed by a signal from the nth unit of shift register 42.
Closed if a logical 1 data bit is present in the bit memory location. If a logical 0 is present in the nth bit memory location, indicating the absence of a part in the nth machining unit, advancement and feeding of the tool 30 in the nth machining unit cannot be sustained.

The crosspiece 94 will be further explained. The same crosspiece shows a contact 94c that displays an automatic selection switch. A contact 94 is provided to prevent further advancement or feeding when the tool of the nth unit reaches its predetermined depth.
d is provided and a contact 94e is provided to prevent the tool from feeding into the part unless the main shaft 26 of the nth machining unit is closed.

The crosspiece 96 will be explained. The crosspiece has a contact 96a that is closed by a feed signal from the feed start device.
and a contact 96b that is closed by activation of the coil 96c.

The crosspiece 98 in FIG. 8 will be explained. The same crosspiece shows a contact 98a that is closed when the nth processing unit is fully advanced. The controller 32 is informed of this type of condition by a signal coupled to the controller from a limit switch in the nth unit, and the limit switch is moved to the full extent of the unit's advance. Crosspiece 98 further includes a timer function box 98b configured to time up to 1/2 second. Therefore, the retention coil 98c of the crosspiece 98 is activated 1/2 second after the nth processing unit is completely advanced.

The crosspiece 100 in the ladder diagram of FIG. 8 will be explained. The same crosspiece shows a contact 100a which is closed when the nth machining unit returns to its original position at the end of the machining unit cycle. Contact 100
Since b is closed by the above time, coil 1
00c is activated and indicates that the processing unit has returned. Contact 100a is closed by a signal provided by a second limit switch on the nth machining unit, the second limit switch being adapted to generate a signal when the machining unit returns to its original position. placed.

The ladder diagram in FIG. 9 will be explained. The diagram shows bars 102, 104 that create the conditions for activating coil 102e, which causes the tool of the nth machining unit to return to its original position at the end of the machining unit cycle. Tool return can be initiated by the "unit return" pushbutton, which closes contact 102a. However, when the tool of the nth machining unit reaches its predetermined depth, the return of the tool is automatically initiated by the contact 104a of the crosspiece 104.

The crosspiece 110 in the ladder diagram of FIG. 9 will be explained. The pier is activated by activation of the retention coil 98c.
Also, the depth coil 11 is activated by the released state of the aforementioned unit return limit switch.
Indicates 0e. However, during a machining unit cycle, if no part is present in the nth machining unit, the unit will not be activated and contact 110a will be prevented from closing. Therefore, the contact points 110a, 1 of the crosspiece 110
10b is shunted by a crosspiece 108. Contact 10
Contact 8a is closed by a signal from the interlock circuit of the controller cycling the processing unit, and contact 108b is closed by a logic 0 in the nth bit memory location of shift register 42. As shown in FIG. 9, by providing the crosspiece 108, the nth
Even if machining unit 22 is not cycled during a machining cycle due to the absence of a part within the unit, a power flow path to coil 110e is created.

When coil 110e is activated, contact 112a
is closed, creating a power flow path through crosspiece 112.

FIG. 10 will be explained. The figure shows a ladder diagram with a number of contacts connected in series, each contact being closed when the depth coil 110e of one processing unit 22 is activated. Activation of coil 114a indicates that the processing unit cycle is complete and the part transfer cycle can begin. The contacts on the rung 114 corresponding to the machining unit without the part remain closed during the machining cycle due to the provision of the rung in the ladder diagram of FIG. 9, as described above. Each of the other contacts of bar 114 is closed when one of the processing units operating during a processing unit cycle completes its processing operation. Therefore, for any given processing unit
The duration of the cycle is less than or equal to the longest cycle time of the processing unit actually operating during the processing cycle.

From the above description, transfer machine 10
However, by repeatedly performing a large number of logical operations,
It will be appreciated that when operated in accordance with the present invention, the results of particular logical operations are determined by the state of various components of the transfer machine and by the contents of the shift register. Instead of performing logical operations by control devices constructed by incorporating specific ladder diagrams, logical operations can be performed by clever interconnection of individual standard electronic components such as AND gates and OR gates. will become clear easily. Shift registers may also include standard hard-wired components. This type of interconnection of parts is easily understood by those skilled in the art in view of the above ladder diagram which clearly shows the various logical operations to be performed.

A further modification of the invention would be to use a suitably programmed digital computer to perform the necessary logical operations.

Obviously, many other modifications and variations of the present invention are possible in view of the above lessons and therefore fall within the scope of the disclosed inventive concept.
The invention may be practiced otherwise than as specifically described.

[Brief explanation of the drawing]

Fig. 1 is a front view showing a generalized type of transfer machine, Fig. 2 is a block diagram showing a control device for instructing the operation of the transfer machine shown in Fig. 1, and Figs. 3 to 10. 2 is a ladder diagram that may be used to configure the control system of FIG. 2 operative in accordance with the present invention; FIG. 10... Transfer machine, 22... Processing unit, 12... Part or workpiece, 32...
Control device, 18... Loading station, 42...
shift register.

Claims (1)

[Claims] 1. A loading station that receives a workpiece to be processed, a plurality of processing units selectively arranged to perform predetermined processing on the workpiece, and a series of workpiece transfer cycles. During one workpiece transfer cycle, each workpiece is moved from one of said machining units to the next, and each workpiece is transferred from an input station to each of said machining units in a predetermined sequence. a transfer device configured to move the transfer device; and a first digital device configured to detect the presence or absence of a workpiece at an input station and detect the presence of a workpiece at the input station before each transfer cycle.
a detection device configured to generate a first signal having a code and generate a second signal having a second digital code if there is no workpiece at the loading station before each transfer cycle; , having a number of discrete digital code storage locations such that each of said processing units uniquely corresponds to one storage location, and receiving said signals from the detection device before each transfer cycle. A digital device connected to the detection device to receive
a code storage device; and a code storage device for a given one of said storage locations if, at the completion of any transfer cycle, a workpiece is placed in the processing unit corresponding to said storage location. The digital code contained in the memory location is comprised of the first digital code and is included in the given memory location if no workpiece is located in the processing unit corresponding to the given memory location. an apparatus for shifting the received digital code in the storage device upon occurrence of the workpiece transfer cycle such that the digital code consists of the second digital code; and Depending on the content, if the given storage location contains the first digital code, the processing unit corresponding to the given storage location is activated to perform a predetermined processing, a selective actuator configured to deactivate the processing unit corresponding to a given memory location if said memory location contains said second digital code; The first digital code is configured such that the transfer of the workpiece occurs after the machining operation is completed in the machining unit that has the longest machining time among the machining units activated due to the presence of the first digital code. - a starting device connected to the transfer device for starting operation of the transfer device when processing operations have been completed in all of the processing units activated by the presence of the cord;・Machine control device. 2. The digital code storage device comprises a shift register having a number of locations for storing discrete digital bits, each of the bit storage locations consisting of one digital code storage location, and the first digital code storage device comprising: each of the codes comprises digital bits having a first logic level; each of the second digital codes comprises digital bits having a second logic level;
The shifting device is configured to transfer one workpiece.
Apparatus as claimed in claim 1, including means for shifting a given digital bit from one bit storage location to the next bit storage location in response to a cycle. 3. If at the beginning of any workpiece transfer period the shift register contains at least one digital bit of said first logic level, said transfer is performed during said workpiece transfer period depending on the contents of said shift register. 3. The device of claim 2, wherein the device is configured to actuate a device. 4. Even though a workpiece is being received in a processing unit corresponding to a particular bit memory location of said bit memory locations, said set bit memory location contains a digital bit of said second logic level. 4. The apparatus of claim 3, wherein the apparatus is configured to generate a signal after a workpiece transfer cycle if the workpiece is transferred.