US3575077A

US3575077A - Controls for traveling head-cutting presses

Info

Publication number: US3575077A
Authority: US
Inventors: Donald F Herdeg; William D Longval
Original assignee: USM Corp
Current assignee: USM Corp
Priority date: 1969-02-14
Filing date: 1969-02-14
Publication date: 1971-04-13
Anticipated expiration: 1988-04-13
Also published as: GB1305981A; FR2035446A5; ZA70984B; DE2006334A1

Abstract

A traveling head cutting press is provided with light-responsive control means operative in accordance with the movements of the operator, without necessitating diversion of the operator''s attention from work manipulation, for initiating platen movement of translation, either in initiating cutting strokes in response to withdrawal of the operator''s hands from the danger zone or in causing traverse movement with the head in following the die placement area along the work. The control means is operative to terminate the platen movement automatically.

Description

United States Patent Donald F. Herdeg Beverly;

William B. Longval, Danvers, Mass. 799,410

Feb. 14, 1969 Apr. 13, 1971 USM Corporation Flemington, NJ.

Inventors Appl. No. Filed Patented Assignee CONTROLS FOR TRAVELING HEAD-CUTTING PRESSES 7 Claims, 13 Drawing Figs.

US. Cl 83/524, 83/534, 83/541,100/53 Int. Cl B26d 5/12 Field of Search 83/5 34,

[56] References Cited UNITED STATES PATENTS 3,204,506 9/ 1 965 Reinhold 83/534 3,329,050 7/1967 Bianchi 83/5 34X 3,389,628 6/1968 Banks et al. 83/534X Primary Examiner-James M. Meister Attorneys-W. Bigelow Hall, Richard A. Wise and George C.

Fuller ABSTRACT: A traveling head cutting press is provided with light-responsive control means operative in accordance with the movements of the operator, without necessitating diversion of the operators attention from work manipulation, for initiating platen'movement of translation, either in initiating cutting strokes in response to withdrawal of the operator's hands from the danger zone or in causing traverse movement with the head in following the die placement area along the work. The control means is operative to terminate the platen movement automatically.

Patented A ril 13, 1971 11 Sheets-Sheet 1 [HI/en ions Donald FHEP day gual 0Pn William B.Lon By zhei/"Azz y Patented April 13, mm 3,57%?! 11 Sheets-Sheet 2 V I; 1-1 1 m q Patented April 13, 1971 3,575,017

11 Sheets-Sheet 5 Patented April 13, 1971 3,5 75,017

11 Sheets-Sheet 6 Patented April 13', 1971 Patented April 13, 1971 11 Sheets-Sheet 8 Patented April 13, 1971 3,575,017

n Sheets-Sheet 9 CONTROLS FOR TRAVELING HEAD-CUTTWG PRESSES FIELD OF THE INVENTION This invention relates to improvements in cutting presses and more particularly to improvements in controls for effecting power-operated movements of the platen of such presses.

DESCRIPTION OF THE PRIOR ART The invention is herein illustrated as embodied in each of two forms of cutting presses of the traveling head type having an upper presser member, or platen which is much smaller than the lower presser member or work support.

One form is similar to that shown in US. Pat. No. 3,389,628, issued Jun. 25, 1968, on an application in the names of David E. Banks et al. In this form, the platen is mounted on the head relative to which it has vertical movement only; its horizontal movement of translation is limited to movement of traverse with the head. The other form, preferred but more expensive, differs chiefly in having the platen mounted on the head for additional movement of translation between a rearward position of rest and forward operating position generally aligned for receiving the thrust of a pressure-operated ram carried in the head. Thus the platen has horizontal movement of translation both in traverse with the head and in forward-backward movement relative thereto as well as vertical movement of translation.

For large run repetitive cutting requiring no discretion of die placement, such presses can be and often are equipped with a die-carrying platen and controls for causing the platen to cycle continuously, moving in sequenced cutting strokes across the width of the workpiece. However, the circumstances of a large share of die cutting makes it desirable that the operator exercise discretion in locating die-cutting means on the work. Examples include dieing out parts of different sizes involving frequent die changes, nesting of the parts and dieing out parts from workpieces of nonuniform character. Accordingly, in using such cutting presses, it has been common. procedure for the operator to position a workpiece on the support and to place and replace a cutting die on the workpiece, operating the press by manually initiating a cutting cycle after each placement to cause the platen to press the die through the workpiece. After every cut the platen must be translated to a rest position sufficiently spaced from its operative position to permit the operator to pick up and replace the die, and, when the operator is ready for the next cut the platen must be brought back over the die. This translatory movement may be programmed as part of or preliminary to a cutting cycle of sequenced movements.

Such cutting is often referred to as semiautomatic because it involves manipulation of the work by the operator in each cutting cycle. The machine itself may be equipped with control means for continuous cycling with programmed delays, for example as disclosed in the above-mentioned patent (Modes 9 and 110). However, a continuous cycling mode of operation requires the operator to adjust his rhythm to that of the machine rather than vice versa as is desirable. Hence all else being equal, it would be preferable in many cases for the operator to control the initiation of each cycle of the cutting press in which cycle the platen would be translated to an operative position over the die from a rest position, caused to press the die, and then returned to a rest position, the portions of this total movement of the cutting cycle suitably being controlled in automatic sequence as for example by sequencing switches actuated in response to movement of the platen to predetermined positions.

Although initiation of each cycle of the press individually has proved desirable, manual actuation for the initiation of such cycles is often detrimental to production because of the time and effort expended in the transfer of the attention and hands of the operator between the die and the actuating means.

Additionally, adjustment of the lateral position of the head to follow the work so that the platen in its rest position tuated means such as jog buttons, for adjusting the position of the head.

SUMMARY OF THE INVENTION It is accordingly an object of the present invention to provide in a cutting press of the traveling head type improved control means operative under the control of the operator, but without the need for transfer of attention and hands to a manually actuated element, for initiatingsuch movements of the platen as may be required during the cutting operation, for example in initiating a cutting stroke movement including return movement of the platen from a rest position toward the die or in adjustment of the lateral position of the head.

It is another object of the present invention to provide in such a press, control means which are operative to initiate horizontal return movement of the platen in response to retracting of the operators hands from the danger zone and thereafter to terminate all further movement without intervention by the operator after not more than a single cutting stroke.

It is another object of the present invention to provide in a press of the traveling head type, improved control means which are responsive to natural movements of the operator in manipulating cutting die means along the work for initiating and controlling traverse movement of the head in following the progress of the die placement area along the work and for thus maintaining the positions of the platen in its rest and operative positions in appropriate relation with the die placement area to insure engagement of the platen with the cutting die means upon initiation of a cutting stroke.

Still another object of the present invention is to provide improved control means for traveling head cutting presses which will reduce operator fatigue in the operation of the press in performing cutting operations involving discretionary die placement and which will enhance production by permitting the operator to give his undivided attention to manipulations in the die placement area.

To these ends, and in accordance with a feature of the present invention a traveling head cutting press is provided with light-responsive control means operative in accordance with the movements of the operator, without necessitating diversion of the operator's attention from work manipulation, for initiating platen movement of translation, either in initiating cutting strokes in response to withdrawal of the operators hands from the danger zone or in causing traverse movement with the head in following the die placement area along the work. The control means is operative to terminate the platen movement automatically.

In accordance with a further feature of the invention, for initiating platen movement including a cutting stroke, the lightresponsive controls include photoresponsive means and means for illuminating said means effective through an optical path extending adjacent the front of the work support whereby removal of the operator's hands from the work support is operative to initiate a cutting stroke.

In accordance with another feature of the invention for initiating movement of the platen with the head in following the die placement area during the cutting operation, the lightresponsive controls include illuminating means effective through paths intersecting the work area on each side of the head for response to movements of the operator in moving dies laterally. In both forms of the illustrative apparatus, the movement of the platen between the rest and operative positions is determined by limit switch means. However it is also contemplated that following initiation of horizontal translation of the platen to the operative position in response to removal of the operators hands, that this component of movement be terminated and the downward vertical component of translation, i.e. the cutting stroke, may be tripped manually when the platen arrives at an operative position over the die.

After termination of the stroke at the bottom of the vertical movement of the platen, the control would automatically cause the platen to be returned to a rest position determined by timing its horizontal translatory movement from operative position. This mode is eminently suitable for a press such as said one form in which the platen has horizontal movement only with the head. In such a mode of operation there is no loss of time in transfer of attention and hands to initiate a movement since this occurs during the already initiated horizontal movement.

Other features and advantages of the invention will best be understood from the following description together with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described further in connection with the attached drawings in which:

FIG. I is a front elevation with parts broken away of a preferred form of apparatus embodying the invention;

FIG. 2 is a right elevation with parts broken away of the apparatus of FIG. I;

FIG. 3 is a section on line III-Ill of FIG. 2',

FIG. 4 is a diagram of the hydraulic system of the apparatus of FIG. I and ofFlG. 9;

FIG. 5 is a truth table relating operating responses and solenoid energization conditions for the hydraulic system of FIG.

FIG. 6 is a diagram of the pneumatic system of the apparatus of FIG. 1;

FIG. 7 is a truth table relating operating responses and solenoid energization conditions for the system of FIG. 6;

FIGS. 80 and 8b constitute a diagram of the electrical system of the apparatus of FIG. 1;

FIG. 9 is a front elevation of a modification embodying the present invention;

FIG. 10 is a side elevation partly in section on an enlarged scale of the portion of the apparatus shown in FIG. 9; and

FIGS. 11a and llb constitute a diagram of the electrical system of the apparatus of FIG. 9.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention is illustrated as embodied in light-responsive control means traveling head cutting presses which are similar in general organization to that shown and described in detail in the aforementioned patent.

Accordingly. referring to FIGS. I through 8b, the illustrative preferred form of press comprises a frame I0 carrying a work support 12.

The work support I2 is adapted to receive workpieces 14 to be cut into work parts by means of a die 16. The upper portion I8 of the frame I0 is provided with rail means extending horizontally above the work support I2 for supporting a head 22 on rollers 24 journaled therein.

The head 22 supports a bearing tube 26 in which a platenbearing cylinder 28 is vertically slideable for raising and lowering a platen 30 in cutting strokes for pressing the die I6 through the work and against the work support 12. Rotation of the platen-bearing cylinder is prevented by the provision of four vertical slide tubes 32 (see FIGS. 2 and 3) connected at their bottom to a slideway 34 in which the platen is mounted to slide between an operative position over the work support and a rearward rest position clear of the support. Platen return springs 36, extend through the slide tubes from the slideway to the upper portion of the bearing tube 26 where they are secured to brackets 38 carried on a bearing tube cover 40 bolted to the tube 26. A hollow piston rod 42 (FIG. 1) extends downwardly from the cover 40 and carries at its lower end a piston 44 having a sliding fit within the inner surface of the cylinder 28.

Means comprising a flexible hose 46 one end of which is connected to piston rod terminal fittings 48, is provided for connecting, through the piston rod and through a port in the bottom of the piston, the chamber beneath the piston with a source of pressure fluid through a pump 50 driven by an electric motor 52 so that when pressure fluid is admitted to the pressure chamber, the platen is caused to descend for pressing the die 16 through the work piece.

Traverse movement of the head 22 is arranged to be effected by means comprising a traverse screw 60 journaled in bearings 62 at opposite ends of the frame portion 18 and threaded with a nut 64 secured to the head 22. The screw 60 is driven by a reversible hydraulic motor 66.

Means for effecting sliding movement of the platen 30 in the slideway 34 forwardly and rearwardly of the work support 14 comprises a pneumatic cylinder 70 secured to the slideway by a bracket 72. The cylinder 70 has a piston 74 (FIG. 6) secured to a piston rode 76 connected to a rearward extension 78 of the platen.

Referring now to FIG. 4, the hydraulic system of the press comprises the pump 50 operated by the electric motor 52 for supplying hydraulic fluid from a sump to the cylinder 28 for providing vertical movement of the platen, and to the traverse motor 66. Supply of fluid to the cylinder 28 is controlled by an Up" solenoid valve 92 and a Down" valve 94 which are connected to the pump 50 and the cylinder 28 for effecting the indicated movement in response to energization of their responsive solenoids. The table of FIG. 5 may be referred to in understanding the operation of the system.

Means for controlling the pressure of the hydraulic fluid supplied by the pump 50 comprises a piloted valve referred to as the Dump" valve. This valve is controlled by a pilot valve 102 operated by a Dump" solenoid 103. When the solenoid 103 is not energized, the valve 100 is piloted by pressure controlled by a relief valve 104 to provide only a small hydraulic pressure. When the solenoid 103 is energized the valve 100 is piloted closed to provide full pressure.

Means for controlling the supply of hydraulic fluid to the hydraulic motor 66 in effecting traverse comprises solenoid valves and 112 respectively arranged for interrupting the supply of fluid from the pump and from the motor to the sump. The direction of flow of the hydraulic fluid through the motor 66 is determined by a third solenoid valve 114. Pressure relief valves 116 and I18 are provided to regulate acceleration and deceleration of the traverse movement of the head. Thus upon deenergizing of the solenoid valve 112, instead of being locked up. the hydraulic motor circuit provides a smooth approach to each new position without overshoot.

Means for controlling the supply of compressed gas, suitably compressed air, to the cylinder 70 in effecting forward-rearward movement of the platen is diagrammed in FIG. 6. Thus, the gas, suitably from a factory source 120, is put through a filter separator I22 from which it branches to three pressure-regulating valves I24, I26 and 128. The gas, after passing through the valve 126 and an oiler 130, is conducted through a valve 132 operated by a solenoid identified as 4 Sol and through one of two passage means 131, 133, according to the position of the valve 132, to the cylinder 70 from which it is exhausted through the other passage means. The passage means 131, I33 comprise check valves I34 and variable restrictions 136. In effecting movement of the platen 30 rearwardly (to the right as viewed in FIG. 6), 4 Sol is not energized, resulting in conditions for rearward movement of the platen from a forward position. Provision is made for checking such rearward movement by application of back pressure. Thus during deenergization of 5 Sol, gaseous communication is established between the pressure regulator valve 128 and the right-hand chamber of the cylinder 70. The relation between the positions of the valves and the forward and rearward movements of the platen will readily be understood from the table (shown in FIG. 7) wherein the energization state of the three

solenoids

4, 5 and 6 are indicated with respect to the function provided. For example, forward movement of the platen 30 is provided by energizing 4 Sol and 5 Sol and checked by gas under pressure from the regulator valve 124 during deenergization of 6 Sol.

Referring now to FIGS. ll, 2 and 3, there is provided lightresponsive means for initiating the operation of the power means in response to changes of illumination thereof for causing translatory movement of the platen from a rearward rest position toward an operative position in accordance with movements of the operator. Thus the control includes illuminating means operative via optical paths establishing a light screen" across the front of the support 12 to illuminate light-sensing means, the illuminating means comprising a lamp 150 mounted on one side of the frame It) and paired with a photocell 152 mounted on the other opposite side. In the illustrative arrangement, three such pairs of lamps and photocells arranged with their light beams directed in alternate directions, have been provided to produce a screen of suitable height and immunity to ambient light for safe operation of the press but it will be understood that any one of many optical arrangements including the use of more than three beams may be provided if desired.

The elements of control means for initiating translatory movement of the platen in causing traverse movement of the head to follow the work in response to lateral movements of the operator will now be described. Thus, mounted on a bar 160 carried by the head 22, are four pairs of lamps and

photocells

161, 162, 163, 164 each arranged in retroreflective coaxial arrangement wherein the photocell of each pair is arranged for sensing illumination by the lamp through an optical path intersecting the working zone on one or the other side of the head. Thus light from the lamp of each pair is beamed" along a path indicated by a dot-dash line (FIGS. 1 and 2) returning to the photocell from reflective tape I66 carried along a rearwardly facing surface of an angle iron 168. The optical paths of the four

pairs

161, 162, 163, and 164 are designated respectively A, B, C and D.

The above-described control elements are incorporated in a control circuit, diagrarnmed in FIG. 8a and 8b and to which reference may be had for an understanding for the following description of operation of the preferred form of press. In referring to FIG. ha, the photocells of the pairs I61, 162, I63 and 164 are shown in lines 1-8, respectively controlling relays A, B, C and D, while the photocells of the light screen shown in lines 9-14 and identified as 152-1, 152-2 and 152-3 respectively control relays H1, H2, and H3 which have their contacts connected in parallel (lines 28-30) and may be considered collectively as H.

In operation, accordingly, at rest the platen 30 is in rearward position and actuating a back limit switch, BLS (FIG. 2) by means of a cam 170 (FIG. 2) carried by the platen. The head 22 will be between left and right traverse limit switches, Ll-ILS and RHLS (FIG. 1). With electrical energy applied to the light beam control circuit and to the hydraulic pump motor while air is supplied to the pneumatic circuit, the operator may initiate his die-positioning manipulation. When the operator is positioning the die within the lateral confines of the head, passage of the operator's hands through the light beam screen energizes one or more of the H relays energizing a relay 8 (line 23) and consequently, a relay 12 (line 40) which cocks" the control for making a cut. When next the operator removes his hands, the relay 8 is deenergized which now energizes 6 Sol and 4 Sol through normally closed contacts in

lines

38 and 39 respectively and the platen moves forward (see FIG. 6). At the end of its forward movement, the platen operates a switch FLS (FIG. 2) by means of the cam 170. This deenergizes 6 Sol, thus braking the motion. FLS also energizes (line 3%) a relay 10 (line 37) which energizes the Down 94! and Dump 102 solenoids (FIG. d) which starts the downward movement of the platen.

An adjustable lower limit switch LLS (FIG. 1) is arranged to be actuated when the platen has reached a lower position in which the die has been driven through the workpiece. Such actuation of LLS, (FIG. 8b, lines 35 and 37), energizes relay 111 which latches itself, temporarily preventing reenergization of the relay 1t), and the platen starts to move upward. When the platen has reached its upper limit, a switch ULS (FIGS. 1

and 8b, line 46) is actuated energizing a relay 14 which energizes 5 Sol (line 42) which is latched in through a relay 13 until the switch BLS is actuated. The relay 13 also operates to deenergize the relay I2 and thus 4 Sol and 6 Sol. The actuation of the switch BLS operates to deenergize 5 Sol and the relay 13, thus returning the conditions to the starting point.

If the operator should pass his hands through the light screen during motion of the platen, 4 Sol and 6 So] are immediately deenergized and 5 Sol energized, reversing the platen.

Frequently, the operator will need to move a die to the right or to the left beyond the lateral confines of the platen 30. In a case where the operator moves the die to the left far enough to interrupt the optical path B of the pair 162, this energizes the relay B and relay 1 (FIG. 8a, lines 3 and 16) and consequently relay 9 and El Sol which is latched in through relay 9, but the head does not traverse at this time. If the hand moves away from the optical path B back to the center, relay 1 is deenergized after a short RC time constant provided in line 15. However, if the hand continues leftward past the path B to the path A in a reasonable time, suitably about a second, during which the RC circuit holds in relay 1, relay 2 is energized and holds itself through a contact in line 17. At the same time relay 7 and relay 1TD (line 24) are energized. Relay 7 energizes l Sol, 2 Sol and the Dump Sol in line 34 which operate to accelerate the head to the left. If the operator had kept the relay B energized while he energizes the relay A, the head would not move due to relay 5 being energized. This feature avoids solenoid chatter due to undesirable feed back. Similar protection is provided against the combinations of A and C, B and D, or C and D. When the head catches up with the new position of the operator's wrist, as he is holding the die in the new position, relay B operates to energize the relay 6. This deenergizes relay 2 which deenergizes relay 7 and hence the three solenoids (1, 2 and Dump), decelerating and eventually stopping the head. The

pressure relief valve

116 and 118 control respectively the acceleration and the deceleration force and coast distance to achieve smoothness. Suitably, acceleration can be greater than deceleration. Operation on the other side of the head is similar. Note that the use of the dual optical paths A and B results in the head following outward motion but prevents the head moving if the movement is inward toward the center; if relay A is operated and then released before relay B is energized, relay 2 is not energized. Thus the control is operative in response to a predetermined sequence of the optical paths A and B to cause the power means to effect traverse movement of the head.

If the head reaches the end of travel before it gets the normal inner wrist-sensing signal as from the path B, the switch LI-ILS is opened which deenergizes the relay 7, and this in turn, 1 Sol, 2 Sol and Dump Sol, stopping the head.

If the operator should quickly reposition the die outside the confines of the head and withdraw his hands before the head meets its normal wrist-sensing B signal from the photocell of the pair 162, H is deenergized which deenergizes relay 8. However, the relay 2 is not deenergized because of the relay 1TD contacts in line 15. This timer had started with the traverse. After it times out it deenergizes the relay 2, thus stopping the head as before. The relay 1TD is adjustable and can be preset by the operator according to the distance he wants the head to index in the absence of a normal wristsensing stop signal. The relay 7 has another function during this type of operation. It prevents the down stroke from being started (line 37) until after the traverse deceleration is started.

When the operator changes from a leftward to a rightward motion, the relay 3 is energized which deenergizes 3 Sol and also the relay 9 which keeps 3 Sol energized throughout deceleration of the leftward motion.

The retroreflective light source and cells are permanently aligned coaxially. The point on the reflective tape where they are directed can easily be adjusted with respect to the head to accommodate the different ways in which different operators might hold the die. By so doing, the head can be made to stop over the die.

A modification comprising a cutting press having a platen mounted on the head but without capability of forward and rearward movement of the platen relative thereto, is illustrated in FIGS. 9, l0, llla and lllb. Here the same general principle of control is used, but with adaptations.

As shown in FIGS. 9 and 10, a slider 200 is mounted for lateral bodily movement along a rail 202 extending transversly of the frame The slider 200 is normally held from sliding movement along the rail by a brake 204 having a solenoid 1BR.

The direction-controlling light beam pairs are not mounted on the head in this embodiment but on the slider 200. The slider also carries a center position microswitch CPS and both a left and a right idle position microswitch, LIPS and RllS respectively. During the tracking of the hand position, the head is at either the left or right idle positions relative to the slider 200. A solenoid, 7 Sol (FIG. mounted on the head couples the slider to the head to make them move together. After the tracking is completed, the solenoid releases the slider, which is held at that place by the brake solenoid 1 BR (FlG. 10), The head then moves along the slider until the center position switch CPS is reached. There the head stops for the cut. After the cut, the head moves away to the same idle position limit switch on the slider from which it started. At this point operation of 7 Sol recouples the slider and head, the slider brake is released and tracking of the hands is again performed.

As with the previously described control, if the operator removes his hands before the light beam reaches him, the time delay ITS makes the head traverse the full index. However, unlike the above-described control, the head must still move the full covering distance along the slider; there can be no overlapping of motions.

When, during tracking, the head moves to the frame limit switches LHLS or RHLS, it stops and the operator realizes that he is unable to place the die any further toward that end. He then switches the selector switch to the opposite position and the head immediately moves to the opposite end of the slider, whereupon the operator can now place the die fully to the end of the machine.

lt is noted that the head in moving from an idle position to the center position on the slider will interrupt one pair of beams, for example, 263' and R64 as shown in FIG. 1?. However, by providing means for the head to maintain interruption during the cut and until it clears to the side, no false tracking signal is created because the direction-controlling light beams purposely do not respond to an interruption that moves from the side to the center position.

In describing the operation of the control in this form of press, the description will be somewhat shortened because of similarity to the operation of the control previously described A right-hand idle position will he used for the description. Thus referring to FEGS. Rita and 11b, insertion of the operator's hands operates the H relay 8 in line 2?? and relay 23 in line 43 to cock the control for a cut. Removal of the hands deenergizes relay 3 and energizes the

relay

22, 1 Sol, 2 Sol, Dump Sol, the relay and 3 Sol; the head moves to the left. When CPS switch is operated, the relay 2t) and the Down Sol are energized while the relay 22 and E and 2 Sol are deencrgized; the Dump Sol stays on; the head is decelerated; the RC time constant in line 54 keeps the

DC relay

25 and 3 Sol on long enough to decelerate the head. The lower limit switch is operated when the cutting cylinder reaches the preset lower limit deenergizing the Down solenoid, the Dump solenoid and energizing the relay 2i and the Up Sol. The contacts of the relay 21 in line 39 prevent the relay 20 from being reenergized when the switch LLS closes again. When the cutting cylinder reaches the preset upper limit, the switch ULS is operated deenergizing the Up Sol in line 45. The

relays

24 and 26 and the l, 2 and Dump solenoids are energized and the head moves to the right. The relay 23 is deenergized by the relay 26 contacts, the relay 26 latches itself and the relay 24 is deencrgized by the relay 2] as soon as the head has left the center position. When the head reaches the side, the switch RIPS is operated, turning off the relay 26 and the solenoids l, 2 and Dump.

Tracking operates in exactly the same way as previously described in normal operation. If the head reaches the righthand limit switch and is automatically stopped, the operator reverses its idle position as follows: the selector switch is turned to Left ldle Position" see FIG. 11b, line 51. This energizes the

relays

26, 25, 3 Sol, 1 Sol, 2 Sol, and the Dump Sol; the left idle position switch finally stops the head by deenergizing the relay 26 etc. Since the relay 7 is not on, the momentary operation of the switch CPS has no effect.

We claim:

1. in a traveling head cutting press having a work support for supporting workpieces to be cut be means including cutting dies superimposed thereon, a platen for pressing cutting dies through workpieces, means for supporting said platen for movement toward and away from the surface of the work support and for movement of translation over the work support, and power means for effecting such platen movements, in combination therewith control means which comprise:

means responsive to light;

means spaced from said light-responsive means and operative along an optical path intersecting a zone adjacent the support surface for illuminating said light-responsive means; means controlled by the light-responsive means in accordance with changes in illumination thereof for in itiating operation of said power means; and said lightresponsive means and said illuminating means being supported for movement of traverse with said head and two of the light-responsive and two of the coacting illuminating means are arranged in operative association to provide first and second laterally spaced optical paths on at least one side of said head and said initiating means is operative in response to interruption of said first and second optical paths in predetermined sequence for causing said power means to effect movement of traverse of said head.

2. Apparatus as in claim 1 in which said movement of traverse is terminated by said control means upon interruption of one of said optical paths whereby the head is stopped upon catching up with a repositioning of the die.

3. Apparatus as in claim I in which said light-responsive means and said illuminating means are carried on a support mounted on the press for bodily movement of translation parallel to the traverse movement of the head, said control means including switch means carried by said support for actuation by movement of said head with respect thereto for determining a rest position of the head and an operative position of the head laterally spaced therefrom along said support, said initiating means being operative in response to interruption of said first and second optical paths to cause said power means to effect lateral movement of said support.

4. in a traveling head cutting press having a work support for supporting workpieces to be cut by means including cutting dies superimposed thereon, a platen for pressing cutting dies through workpieces, means for supporting said platen for vertical movement toward and away from the surface of the work support and for horizontal movement of translation thereover, and power means for effecting such movements, a control comprising:

a. means responsive to light;

b. means spaced from said light-responsive means and operative along an optical path intersecting a zone adjacent the surface of the support for illuminating said light-responsive means to cause changes in the illumination of the light responsive means in response to manipulation of the work;

c. means for making said light-responsive means immune to variation in the ambient light adjacent the machine;

d. means controlled by aid light-responsive means in accordance with changer in illumination thereof for initiating the operation of said power means in causing a predetermined movement of said platen; and

e. means responsive to movement of said platen to a predetemiined position for terminating operation of said power means in efiecting movement of the platen.

5. Apparatus as in claim 4 in which said light-responsive means and said illuminating means are associated to provide an optical path extending from side to side adjacent the front edge of the work support and additionally a pair of laterally spaced paths on at least one side of said head, said paths intersecting a work zone beside the head, and in which said initiating means is operative in response to interruption of said pair of optical paths in predetermined sequence and subsequent restoration of the optical paths along the front of the work support, as caused by an operator moving a die laterally and then removing his hands from the work support, for causing said power means to effect movement of traverse of the head in following the die laterally for a predetermined interval and thereafter to effect the movement of the platen toward the surface of said work support.

operative to initiate' operation of said power means in response to interruption of the illumination of said light responsive means by said illuminating means followed by restoration of said illumination, said initiation occurring upon said restoration.

7. Apparatus as in claim 4 in which said means for making said light-responsive means immune to ambient light comprises first and second light-responsive means mounted on opposite sides of a front frame of the press and first and second illuminating means mounted on opposite sides of the front frame, each of said illuminating means being cooperative with both of the light-responsive means on the opposite side of the frame to control the initiating means and in which said initiating means is controlled by either of said light-responsive means.

Claims

1. In a traveling head cutting press having a work support for supporting workpieces to be cut be means including cutting dies superimposed thereon, a platen for pressing cutting dies through workpieces, means for supporting said platen for movement toward and away from the surface of the work support and for movement of translation over the work support, and power means for effecting such platen movements, in combination therewith control means which comprise: means responsive to light; means spaced from said light-responsive means and operative along an optical path intersecting a zone adjacent the support surface for illuminating said light-responsive means; means controlled by the light-responsive means in accordance with changes in illumination thereof for initiating operation of said power means; and said light-responsive means and said illuminating means being supported for movement of traverse with said head and two of the light-responsive and two of the coacting illuminating means are arranged in operative association to provide first and second laterally spaced optical paths on at least one side of said head and said initiating means is operative in response to interruption of said first and second optical paths in predetermined sequence for causing said power means to effect movement of traverse of said head.

3. Apparatus as in claim 1 in which said light-responsive means and said illuminating means are carried on a support mounted on the press for bodily movement of translation parallel to the traverse movement of the head, said control means including switch means carried by said support for actuation by movement of said head with respect thereto for determining a rest position of the head and an operative position of the head laterally spaced therefrom along said support, said initiating means being operative in response to interruption of said first and second optical paths to cause said power means to effect lateral movement of said support.

4. In a traveling head cutting press having a work support for supporting workpieces to be cut by means including cutting dies superimposed thereon, a platen for pressing cutting dies through workpieces, means for supporting said platen for vertical movement toward and away from the surface of the work support and for horizontal movement of translation thereover, and power means for effecting such movements, a control comprising: a. means responsive to light; b. means spaced from said light-responsive means and operative along an optical path intersecting a zone adjacent the surface of the support for illuminating said light-responsive means to cause changes in the illumination of the light responsive means in response to manipulation of the work; c. means for making said light-responsive means immune to variation in the ambient light adjacent the machine; d. means controlled by said light-responsive means in accordance with changes in illumination thereof for initiating the operation of said power means in causing a predetermined movement of said platen; and e. means responsive to movement of said platen to a predetermined position for terminating operation of said power means in effecting movement of the platen.

6. Apparatus as in claim 4 in which said initiating means is operative to initiate operation of said power means in response to interruption of the illumination of said light responsive means by said illuminating means followed by restoration of said illumination, said initiation occurring upon said restoration.