US 3165140 A
Description (OCR text may contain errors)
Jan. 12, 1965 M. w. HAZELTON ETAL 3,165,140
MULTIPLE STOP DEVICE FOR PRESS BRAKES AND THE LIKE Filed July 19, 1961 3 Sheets-Sheet 1 INVENTORS u 0 F: k N mnw END Z N RAE mwq. r 8 W1 n m d m R m M .C A Y B .m 1 6 8 .1
1965 M. w. HAZELTON ETAL 3,
MULTIPLE STOP DEVICE FOR PRESS BRAKES AND THE LIKE Filed July 19. 1961 3 Sheets-Sheet 2 INVENTOR. MERRILL W. HAZEL'I'ON, JOHN J. ERHART AND BY CARL J. Os-rennolzF,
6w 4 ATTORNEYS.
Jan. 12, 1965 M. w. HAZELTON ETAL 3,165,140
MULTIPLE STOP DEVICE FOR PRESS BRAKES AND THE LIKE Filed July 19. 1961 3 Sheets-Sheet s BY CARLJ- OsreuooRF,
ATTORNEYS United States Patent hit) Fiied Italy 19, 1961, Ser. No. 125,204 8 Ciaims. (Cl. 153-121) This invention relates to a multiple stop device for press brakes and the like wherein it is desired to per form on a press brake a series of bending operations wherein the material is to be bent to a different degree at each operation.
In a press brake, the amount of bend produced in a single operation of the ram can be accurately determined by the depth to which the upper die secured to the ram enters into the lower die fixed upon the bed. If a single piece of sheetmetal is to receive a plurality of bends of different angularities, it is desirable to provide an arrangement in accordance with which the ram of the press brake would move downward different amounts on successive strokes. It would then also be desirable that the machine have automatic means whereby such a particular cycle of strokes could be repeated so that if a large number of workpieces are to be given a series of bends of varying degrees, the cycle which would complete one workpiece could be automatically repeated without an adjustment for additional workpieces.
In an operation such as has been outlined above, it is also desirable that compensation may be made for small diiferences in gauge of the pieces being worked upon without disturbing the relationship between the various depths of stroke.
It is also highly desirable that the apparatus be capable of setting to repeat a cycle of any desired number of strokes and to indicate at any time which stroke of the cycle will be carried out on the next operation of the machine. 7
It is also desirable that for one reason or another the operator be able to cause the machine to skip a particular stroke in a cycle.
Accordingly, it is the general object of the present invention to provide apparatus in a press brake and the like which will accomplish the various desired features generally described above. It is another object to provide apparatus which is relatively simple and which may be installed on an existing machine or built into a new machine.
These and other objects of the invention which will be described in more detail hereinafter or which will be apparent to one skilled in the art upon reading the specifications, we accomplish by that certain construction and arrangement of parts of which we shall now describe an exemplary embodiment.
Reference is made to the drawings forming a part hereof and in which: 7
FIGURE 1 is a fragmentary perspective view of a typical press brake showing the general location of the apparatus of the present invention.
FIGURE 2 is a fragmentary elevational view of the portion of the apparatus as seen from the near end of the perspective view of FIGURE 1.
FIGURE 3 is a fragmentary elevational view as-seen from the right of FIGURE 2'." 1
FIGURE 4 is a fragmentary wiring diagram.
FIGURE 5 is a front elevational view of the control box.
FIGURE 6 is a fragmentary Wiring diagram of another portion of the apparatus; and I aiaise Patented Jan. 12, I965 FIGURE 7 is a general wiring diagram showing manual operation.
I In a copending application of Hazelton and Ostendorf, Serial No. 784,499 filed January 2, 1959, and now Patent No. 3,041,963, and copending herewith, there is dis closed a stop device for press brakes and the like. It is one of the features of the disclosure of said application that a stop device is mounted to the bed of the brake and a limit switch is mounted on the ram so that when the ram descends, the limit switch abuts the stop and terminates the downward movement of the ram. The stop member is adjustable very accurately by means of a hand wheel, at the front of the machine having associated therewith a counter-device calibrated in thousandths of an inch. In this way, the depth of movement of the ram may be accurately controlled.
According to the present invention, we mount on the member which constitutes the bottom stop in said copending application, a plurality of additional stop members which are individually capable of adjustment with respect to said member. These stop members may be micrometer type adjustments and we mount upon the ram an equal number of limit switches arranged to be actuated respectively by contact with the various additional stop members. In this way the additional stop members may be individually adjusted with great accuracy with respect to the built-in stop and yet the built-in stop and the additional stop members may all be adjusted as a unit without disturbing the relationship between them.
We provide for manual operation whereby the operator may select any particular one of the preset stops for use on any stroke of the machine and we also provide for cyclic operation by means of a multiwafer stepping device.
Referring now in more detail to the drawings, we have shown in FIGURE 1 a press brake having a bed 10 and side frames of which the near side frame is indicated at 11. Each of the side frames carries ways upon which a ram 12 is arranged to be reciprocated. The ram is preferably operated by hydraulic power. In the copending application above referred to, and to which reference is made for a' fuller understanding of the basic stop arrangement, we secure to the bed 16 a plate 13 which is parallel to but independent of the side frame 11. On the plate 13 is mounted a gear box 14 containing a pair of bevel gears, one of which is rotated by means of a shaft 15 from the front of the machine by rotation of a hand wheel 16. Rotation of the hand wheel 16 is transmitted through the gearing in the box 14 to a vertical shaft 17 which has a threaded portion engaging the stop member 18. The shaft 1% is stationary and passes through a hole in the member 18 to prevent rotation of the member 18 when the shaft 17 is rotated, so that the movement of the member 13 upon rotation of the shaft 17 is only upward or downward.
Within the casing element 20 at the front of the machine is an indicating device which may be calibrated in thousandths of an inch by means of which the stop 18 can be very accurately adjusted.
The ram has secured to it a member 21 which houses a limit switch adapted to be engaged by contact with the stop member 18. This limit switch is shown in FIG- URE 3 and 22.
According to the present invention, we secure to the member 18 a mounting member 23 and upon the member 23 we mount an additional number of stop elements, each of which is individually adjustable. In the figures We have illustrated three such stop members at 24, 25 and 26. At 27, 28 and 29 we have indicated conventional micrometer barrels by means of which the stop elements 24, 25 and 25 respectively may be raised and lowered by very accurately measured amounts. The mircrometer adjustments 27, 28 and 29 will be calibrated in thousandths of an inch.
We associate with the limit switch 22 additional limit switches 30, 31 and 32 which will move with the ram. These are also contained within the casing member 21. A spring member is associated with each of the stop members 24, 25 and 26 as shown, so that after contact is made with the stop member which extends farthest upward, it and other stop members can be depressed without damage until the lowermost stop member actuates those respective limit switches to stop downward movement of the ram.
Other portions of the apparatus which appear in the figures do not pertain to the present invention and need not be described. For further description of such elements, reference may be had to the copending application, Serial No. 784,499, referred to above.
Manual operation of the device is achieved very simply as indicated in the diagram of FIGURE 7, wherein the same numbers as used in FIGURES 1 to 3 inclusive have been applied to the various switches. Assuming first that the main bottom stop 13 has been adjusted for the deepest penetration of the dies upon movement of the ram, the remaining bottom stops are adjusted for other depths which may be required. It will be clear from FIGURE '7 that the operator may simply manually actuate any one of the four switches 22, 39, 31 or 32 to place it in operative condition to stop the ram after it has been started by means of the foot switch 33.
For automatic operation, the device is, of necessity, more complex. in FlGURE we have illustrated the control panel. At 34 there is indicated a switch having two positions, one of which is manual and the other of which is automatic. At 35 we have illustrated a cycle switch which can be placed in an indexed position to provide for a cycle of two, three or four strokes. At 36 there is shown a pushbut-ton switch which has a purpose of advancing a cycle as will be described in more detail hereinafter;
.is a four gang switch. The various positions of the gang switch 35 are indicated in FIGURE 4 at 35a, 35b, 35c and 35d. The indicator 41 is shown in FIGURE 6. The automatic operation is achieved by means of a stepping relay of which the coil is shown at 42. The stepping relay hasfour decks, all of which step as a unit under the influence of the coil 4.2 and these decks are indicated at 'W, X, Y and Z. At the left hand end of FIGURE 4 there is illustrated in conventional manner the manualautomatic switch 34. For manual operation the contactor 43 is closed as indicated by the star under the letter M and for automatic operation the contactor 44 is closed as indicatedby the star under the letter A.
The operation of a stepping relay is not a part of this invention and is well known so that a detailed description thereof is thought to be unnecessary. Because there are in the illustnated embodiment a maximum of four strokes in the cycle and because the particular stepping relay we had available had 11 steps, it will be observed that steps 5 through 11 are shorted out by means of the conductor 45. Similarly, in deck X connections for posi tions 5 to Hare shorted out. In decks W and Z this has not been done because as will clearly appear it is unnecessary to the functioning of the apparatus. At 46 2- associated with the deck Y there is a conventional home contact and at :7 there is il ustrated a jumper between interrupter contact 58 which is normally closed and a home contact which is normally open. A similar interrupter is shown at St? associated with deck W and this functions as a holding circuit during stepping and homing operations. The advance cycle contaclor is shown at 35 and the contactors operated by the automatic down relay and which are normally closed are indicated at 51. it is believed that the operation of the device may now be understood. An automatic down relay (not a part of the present invention but described and disclosed in said copending application) controls the switch Ell of FIG- URE 4 in that when the ram reaches the top 0? its stroke and actuates a suitable top limit switch, an automatic down relay is energized and this causes the contactor El to open. The contactor 51 remains open during the down stroke of the ram but is deenergized when the bottom limit switch is actuated. When the bottom limit switch is actuated the contacor 51 again closes and it is the closing of the contactor Ell which energizes the coil 42 to actuate the stepping relay. Thus, when the ram reaches the bottom of its stroke, the stepping relay is energized and produces a stepping of all of decks W, X, Y and Z. hen the coil 42 is energized. the contactor d9 closes and it remains closed until the interrupter d8 opens, which takes place each time the coil 42 is energized. The interrupter 48 recloses and the coil 42 is deencrgized.
Assuming now that the apparatus is set up to perform an automatic cycle of four strokes and that these strokes are to be performed in the order A, B, C, D, the switch 37 will be set for A, the switch 33 will be set for B, the switch 3) will be set for C and the switch ill will be set for D. Stroke A will be controlled by the limit switch 22, B by the limit switch 3%, C by the limit switch 31 and D by the limit switch 32. It will be clear that on the next stroke of the ram, the coil 52 of the stepping relay will cause the stepping relay to advance to the number 2 position. This will establish a circuit through deck W, switch at position B through the switch 3% which will be placed in position to be actuated by its corresponding bottom stop 24.
On the next operation, the stepping relay will have advanced to position 3 whereupon a circuit is established through deck W. switch 39 at position C to place switch 31 in the circuit. On the next step, at position 4, a circuit will be established through deck W to switch ll at the D position, thus placing switch 32 in operative relation to the circuit.
On the next operation of the relay when it advances to position 5, the decks X and Y are provided to provide it with the jumper from steps 5 through ll, whereby to cause the stepping relay to home and return to the one position so that on the next operation a circuit will he established through deck W, switch 37 at position A to place the basic limit switch 22 in the circuit.
It will be observed that deck Z is connected to the visual indicator which is provided with matrices of bulbs to indicate visually the numerals l, 2, 3 or 4, and because these require a higher voltage, this circuit is fed through a transformer 52 which converts the standard volts A.C. to 220 volts. Deck Z of course is a part of the four deck stepping relay which has been described.
It the switch 35 is positioned at either position number 2 or 3 to provide with a two stroke cycle or three stroke cycle operation, it will be clear that the four gang cycle switch 35a, 35b, 35c, 35d will short out the additional steps of the stepping relay to cause it to home after two steps or three steps respectively.
If the apparatus is set up, for example, to perform a four stroke cycle and the fourth step is indicated at 41 to be the next stroke to be performed, if the operator desires to skip one or more succeeding strokes he may accomplish this by actuating the contactor 35 which manually performs the same function which is automatically performed by the contactor 51. In other words, this energizes the coil 42 of the stepping relay causing it to advance to the next step. In the particular instances described, this would cause the stepping relay to home and return to the number 1 position and the numeral 1 would then appear at 41.
It will be clear that the limit switch 22 is the normal built-in bottom limit switch disclosed in the copending application referred to and which is adjusable from the front of the machine by the hand wheel 16. The switches 3t 31 and 32 are all adjustable in relation to each other and to the switch 22. After all of these switches are adjusted, they may then be moved as a unit by the hand wheel 16 without disturbing the relationship between them so that if a piece or" metal, which is, for example, .002 inch thicker than the previous piece, is to be put through the bending operations, the hand wheel may be adjusted to raise the members 18 and 23 by .002 inch without disturbing the relationship between the switches 22, 30, 31 and 32.
From the foregoing description, it will be seen that we have provided a very versatile arrangement for use with press brakes and the like and it will be clear that while we have disclosed three additional adjustable stops and corresponding limit switches, this is not to be considered as a limitation upon the invention. Any desired number of limit switches and botom stops may thus be provided within the limitation of the number of steps available on the stepping relay. It will also be clear that minor modifications of various kinds can be made without in the least departing from the spirit of the invention. We therefore do not intend to limit ourselves otherwise than as set forth in the claims which follow.
Having now fully described the invention, what we claim as new and desire to secure by Letters Patent is:
1. In a press brake and the like having a bed and a ram reciprocable with respect to said bed; a bottom limit switch, and a member carrying a bottom stop, one of said switch and member being mounted on said bed and the other on said ram, and said member being adjustable to determine the point at which said bottom limit switch is actuated by said bottom stop to stop downward move ment of said ram, a plurality of additional bottom limit switches mounted adjacent said first mentioned limit switch, and a plurality of additional bottom stops mounted on said member, each of said additional bottom stops being adjustable with respect to said member, and an operative electric circuit including switch means for placing any and all of said limit switches selectively into operative relation to said circuit, and means for rendering said selected limit switches operative in any sequence responsive to successive strokes of said ram to provide a cycle of operation wherein the downward movement of said ram'is stopped at difierent points on successive strokes in said cycle, whereby all of said bottom stops may be adjusted as a unit to compensate for variations in thickness of the material being operated upon, without disturbing the settings of said stops in relation to each other.
2. A structure according to claim 1, wherein means are provided for selecting the number of strokes of said ram to constitute said cycle.
3. A structure according to claim 2, wherein visual means are provided to indicate at any time the number of the stroke in said cycle which will be constiuted by the next stroke of said ram.
4. The structure of claim 3, wherein means are provided for passing over any desired number of strokes in said cycle.
5. A structure according to claim 1, wherein said operative electric circuit and said means comprise a number of selector switches equal to a maximum number of strokes per cycle, each of said switches having a number of selection positions equal to the number of said limit switches, a stepping relay, means for energizing said stepping relay at each stroke of said 1am, said stepping relay arranged to place said selector switches in an operative circuit one for each step in sequence, a number of operative circuits each including one selector switch and selectively any of said limit switches, whereby when a selector switch is energized one of said limit switches is placed in operative relation to said circuit.
6. A structure according to claim 5, wherein means are provided to cause said stepping relay to home after any desired number of strokes of the ram less than the maximum number of strokes per cycle.
7. A structure according to claim 6, wherein a series of numeral indications, one for each stroke of said maximum number of strokes per cycle are provided, and wherein operative connections are provided between said stepping relay and said series to cause one of said series of numeral indications to indicate after each stroke of said ram the number of the next stroke in said cycle.
8. A structure according to claim 7, wherein a manually operated switch is provided to energize said stepping relay without operation of said ram, to pass over any desired stroke of said cycle.
References Cited by the Examiner UNITED STATES PATENTS 2,543,759 3/51 Cannon et a1. 1532l 2,797,724 7/57 Walldow 15321 2,837,928 6/58 Meredith 15333 2,840,135 6/58 Fowler 153-21 3,044,289 7/62 Rexford -256 XR CHARLES W. LANHAM, Primary Examiner. WILLIAM J. STEPHENSON, Examiner.