US2949145A - Safety latch and release devices for wipe forming machines - Google Patents

Description

Aug. 16, 1960 P. P. MATTHEWS SAFETY LATCH AND RELEASE DEVICES FOR WIPE FORMING MACHINES 4 Sheets-Sheet 1 Filed Sept. 4, 1958 Gltorneg aw 7)? [Bummer I OW m m A G [IQ Aug. 16, 1960 P. P. MATTHEWS 2,949,145

SAFETY LATCH AND RELEASE DEVICES FOR WIPE FORMING MACHINES Filed Sept. 4, 1958 4 Sheets-Shae 2 fix /Z.9

Aug. 16, 1960 P. P. MATTHEWS 2, 5 SAFETY LATCH AND RELEASE DEVICES FOR WIPE FORMING MACHINES Filed-Sept. 4, 1958 4 Sheets-Sheet 3 34001.5 ZJTCH/NG 0675M? arse/a w/va 90 Ill/F750 er Jae/Iva as 7v APPlY ozn-wr :1, av

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Aug. 16, 1960 P. P. MATTHEWS SAFETY LATCH ANDRELEASE DEVICES FOR WIPE FORMING MACHINES Filed Sept. 4, 1958 P P 101a) [9204, m-za.

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POWER APPL/ED J'Pe/NG' EFL EA JED (ll/T 6 Zhwentor Ctttorneg SAFETY LATCH AND RELEASE DEVICES FOR WIPE FORMING MACHINES Peter P. Matthews, Willoughby, Ohio, assignor to The Cyril Bath Company, Solon, Ohio, a corporation of Ohio Filed Sept. '4, 1958, Ser. No. 759,075

12 Claims. (Cl. 153-40) This invention relates to metal forming machines of the general type disclosed in United States Letters Patent Nos. 2,514,830 and 2,514,831, issued July 1-1, 1950 to Cyril J. Bath and United States Patent No. 2,810,421, issued October 22, 1957 to S. M. Dolney et al., and particularly to a safety latch and release device for the wipe forming mechanism of the machines whereby, upon predetermined excessive components of force being imposed on the wipe forming mechanism in a direct-ion transversely of its normal line of thrust toward the side face of the die, the mechanism is released so that the force is relieved and damage to the wipe forming mechanism and certain other parts of the machine is prevented.

The above identified patents disclose a metal forming machine for forming elongated strip stock by combined wipe and stretch forming, and comprises broadly a power driven turntable rotatable about an upright axis and carrying a side face die about which a length of metal stock is to be formed. In forming the stock, one of its ends is anchored in fixed position relative to the die and the other end is clamped to a fluid pressure operated stretch forming piston and cylinder assemblage by which the stock is subjected to yieldable tension endwise during rotation of the table so that the stock is stretched as it is wrapped about the die face.

In addition, a wipe forming mechanism is provided and has a Wiping shoe which is applied by a fluid perated piston and cylinder assemblage against the stock to press it yieldably against side face of the die during the stretch forming operation.

With these machines, the stock may be stretch formed, or wipe formed, or concurrently wipe and stretch formed. Since it is becoming more common practice to use combined wipe and stretch forming under most conditions, and since the controls of the forming mechanisms are interrelated, the present invention is described herein as applied to a combined wipe and stretch forming machine.

The present invention, however, is more specifically concerned with the wipe forming mechanism and the prevention of damage thereto and to other parts of the machine by faulty operation, or improper die location, or extraneous equipment inadvertently placed on or near the turntable.

As pointed out in the above Patent No. 2,514,830, the wipe forming mechanism is mounted for swinging to different adjusted positions about an upright axis offset from the table axis. Shear pins lock the mechanism in adjusted positions, these shear pins being adapted to shear off and relieve the mechanism for free swivelling when excessive components of force are applied to the wipe forming shoe in a direction transversely of the line of thrust of the Wipe forming mechanism. However, shear pins effective for protecting the mechanism by shearing off when a predetermined transverse component of force is applied to the wiping shoe While the piston is extended are not weak enough to shear off and thus States Patent Ofiice 2,949,145 Patented Aug. 15, 1960 protect the mechanism from an equal transverse component of force applied to the wipe shoe while the piston is fully retracted. Conversely, shear pins sufficiently weak to be sheared off by such a maximum force when the piston is fully retracted, are not strong enough to hold the mechanism in operating position against transverse components of force considerably below that maximum force but well within the range required for effective wipe forming when the piston is fully extended.

In accordance with the present invention, therefore, a safety release'device' is provided for latching the wipe forming mechanism in different adjusted rotated positions about its upright swivelling axis andfor holding the mechanism in the latched position with a latching force which is proportionally increased as the piston is extended and proportionally decreased as the piston is retracted, whereby the device releases the mechanism Whenever a preselected maximum component of force is applied to the wipe shoe transversely of the line of thrust of the mechanism, regardless of whether the piston is in fully extended position, or fully retracted position, or is in any of the intermediate positions therej between.

Other objects and advantages will become apparent from the following description wherein reference is made to the drawing, in which:

Fig. 1 is a top plan view of an apparatus embodying the present invention; I

Fig. 2 is a front elevation of the apparatus illustrated in Fig. 1;

Fig. 3 is a vertical sectional view taken on the line 33 in Fig. 1;

Fig, 3a is an enlarged fragmentary bottom plan view of '1 portion of the apparatus illustrated in Fig. 3 and is taken on line 3a3a thereof;

Fig. 3b is a fragmentary vertical sectional view of part of the apparatus illustrated in Fig. 3 and is taken on line 3b-3b thereof;

Fig. 4 is a diagram of the hydraulic operation system of the machine and safety release device; and

Fig. 5 is a wiring diagram showing the control 'of the hydraulic system.

Referring to the drawings, the apparatus comprises a main frame 1 and a lateral frame 2. A turntable 3 is mounted on the frame 1 for rotation about an upright axis 4 and is adapted to support a side face die D about which the stock S is to be formed. The table 3 is driven by a suitable ring gear 5, driven by pinion gear 6 which, in turn, is driven by a suitable worm gear reducer 7, containing a conventional electric, spring-released clutch 8 which is normally held in released condition by a suitable spring but is engaged upon the energization of its self-contained power applying means, as will be more fully described hereinafter. j

The worm gear reduction mechanism is driven through the clutch mechanism 8 by means of a variable speed reducer 9 which is driven, in turn, by an'electric motor 10.

Mounted on the frame 1 for reciprocation longitudinally thereof in suitable g-uideways 11 is a carriage 12 on which a stretch forming hydraulic piston and cylinder assemblage 13 is supported for swinging about an upright axis 14. The assemblage 13 comprises a cylinder 15 in which is operable a piston 16 having a piston rod 17 to which a stretch forming head 18 is connected. The stretch forming head 18 is arranged to be clamped to one end of the length of stock S to be stretch formed about the die D. A suitable clamp 19 is secured on the table 3 for clamping the other end of the stock S in fixed position relative to the side face of the die D.

The carriage 12 is yieldably urged in a direction away from the turntable by means of suitable supplemental pishaving rods 23, are operable.

ton and cylinder assemblages which are arranged at opposite sides of the path of the carriage. The assemblages 20 comprise cylinders 21 in which pistons 22, The cylinders 21 are fixedly connected to the frame 1 and the rods 23 are fixedly connected to the carriage 12. Fluid pressure is supplied to the head ends of the cylinders 21 for yieldably urging the carriage 12 away from the table 3 and die D so as to apply yieldable tension to the stock as it is being wrapped on the die by rotation of the table, all as more fully described in the above entitled patent.

On the frame 2 is a suitable trackway 25 which extends generally endwise of the side face of the die D or alongside the periphery of the table 3. Mounted on the trackway 25, for reciprocation therealong, is a carriage 26 to which a saddle 27 is connected by a pivot 28 for swivelling in a plane parallel to the top of the table 3. Mounted on the saddle 27 is a piston and cylinder assemblage 29 comprising a cylinder 30 and a piston 31 having a rod 32. Also mounted on the saddle 27 is a slide 33 operable in suitable slideways extending parallel to the axis of the assemblage 29. At its forward end the slide 33 carries a pedestal 34 on which is mounted a wipe forming tool, such as the shoe 35, which is adapted to engage the stock and press it firmly against the side face of the die when pressure fluid is admitted to the head end of the cylinder 30.

As more fully described in U.S. Patent 2,810,421, it is desirable for a number of forming operations that the wipe forming assemblage 29 be reciprocable transversely of its axis endwise of the face of the die D and also that it be swingable to different positions about the upright axis of the pivot 28. For reciprocating or traversing the carriage 26 along the trackway 25, a traversing hydraulic piston and cylinder assemblage 37 is provided, this assemblage comprising a cylinder 38 fixedly secured to the side frame portion 2 and having a piston 39 with a piston rod 40 which is connected to the carriage 26 and which extends parallel to the trackway 25. Mounted on the extension 41 of the carriage 26 is a ram swivelling hydraulic piston and cylinder assemblage 42, comprising a cylinder 43, a piston 44 and a rod 45 connected to the saddle 27. The connections between the rod 45 and the saddle 27 and between the cylinder 43 and the carriage extension 41 are pivotal so that the piston and cylinder assemblage 42 can maintain the proper alignment as it is operated to swing the saddle 27 about the axis of the pivot 28. Fluid pressure is supplied to the head end of the cylinder 30 for applying the shoe 35 to the stock under yielding pressure, and to the rod end of the cylinder 39 for retracting the shoe 35.

It is to be noted that in these operations the die D arrangement on the table, or the die shape is such that the side face of the die does not have the same distance at all times from the axis 4 of the table.

Preferably the die D is mounted on the table so that its side face travels as nearly as practicable endwise transversely of the axis of the assemblage 29 at the instantaneous point of contact of the die and the wiping shoe 35 and that the side face travels as nearly as may be flatwise parallel to the axis of the assemblage 29 at the instantaneous point of contact. However, it often becomes necessary, because of the die shape or its position on the table, that the flatwise approach of the side face of the die to the wipe forming shoe is to a great extent transversely of the axis of the assemblage 29 and, consequently, instead of the force of engagement of the shoe and die being wholly or predominantly axially of the assemblage 29, there is a very large component directed laterally of the axis of the assemblage 29. It is because of these factors, as explained in Patent No. 2,810,421, that the traversing of the wipe forming assemblage along the trackway 25 and the swivelling of the assemblage about the axis of the pivot 28 are provided. At times, too, an operator neglects to traverse or swivel the assemblage 29 properly. Again, it may be that extraneous pieces of equipment are left fastened to the table in such a position as to strike the shoe in a direction transversely of the axis of the assemblage 29 and impose thereon excessive components of force which are apt to damage the structure either of the wipe forming assemblage or of some other portion of the equipment.

To prevent damage from such causes, a safety relief device is provided for latching the assemblage 29 in the particular position desired about the axis of the pivot 28 and for releasing the assemblage 29 if such components of force become excessive.

In this connection it is to be noted that if customary shear pins were provided for securing the saddle 27 to the table 26 in any adjusted position so as to prevent the swivelling of the saddle about the axis of the pivot 28, these shear pins would have a predetermined fixed resistance to shear. Therefore, if a given force F were applied laterally of the shoe 35that is, in a direction circumferentially of the table or transversely of the axis of' the assemblage 29the resultant turning moment imposed on the saddle 27 and assemblage 29, tending to swing them about the axis of the pivot 28 would vary considerably depending upon how far from the axis of the pivot 28 force F were applied. Thus, if the piston rod of the assemblage 29 were greatly extended, the force F would create a large turning moment about the axis of the pivot 28 whereas, if the rod of the assemblage 29 were retracted, the same force F would create a much smaller turning moment. But since both moments would have to be resisted by the same shear pins at the same distance from the pivot 28, shear pins would be unsuitable. If they were strong enough to resist the turning moment imposed by the force F when the assemblage 29 were fully extended, they would be so strong that a force many times F would be necessary to shear them off when the assemblage 29 were fully retracted. As a result, assuming that the force F were the maximum predetermined force allowed for safety, the equipment would be badly damaged before the pins would be sheared off if it were applied while the assemblage was retracted.

. On the other hand, if the pins were sutficiently weak so that they could be sheared off by the force F when the assemblage 29 were in a fully retracted condition, they would be so weak that, were the assemblage 29 fully extended, a force much less than the force F and well within the range required for wipe forming, would cause the pins to shear off so that sufficient forming force for many purposes would not be obtainable.

The safety release device of the present invention releases the saddle 27 for swinging about the axis of the pivot 28 when the force component F reaches a predetermined maximum, regardless of whether the assemblage 29 is in fully extended position, in fully retracted position, or in any of the positions in between. The latching force resisting rotation or swivelling of the saddle 27 about the axis of the pivot 28 is varied in relation to the extension and retraction of the assemblage '29 by the device so that the applied force component F at which the release occurs, can be kept constant or properly proportioned. In addition, means are provided for stopping the equipment when the force component F exceeds a predetermined maximum allowable and the saddle 27 and assemblage 29 are released.

The safety latch and release device comprises a gear segment 50 which is mounted in fixed position on the carriage 26 and is coaxial with the pivot 28. A toothed detent 51, the teeth of which are shaped for meshing with those of the gear segment 50, is mounted in a suitable slideway 52 on the saddle 27 for movement radially of the segment 5) in all swivelled positions of the saddle 27. Also mounted on the saddle 27 is a latching piston and cylinder assemblage 54 including a cylinder 55 and a piston 56 having a piston rod 57, which is connected to the detent 51 for yieldably urging the detent along the slideway 52 toward the gear segment 50. Thus, in any swivelled position of the saddle '27, upon admitting pressure fluid to the head end of the cylinder 55, the piston 56 is operated to urge the detent yieldably toward and into meshing relation with, the ring gear segment 50, thus causing a yieldable intermeshing of the teeth of the detent and gear for locking the saddle '27 in fixed rotated position about its pivot on the carriage 26.

Assuming a force component F is applied laterally of the axis of the assemblage 29, the turning moment imposed thereby would be resisted by the interengaged teeth of the gear segment 50 and of the detent 51. However, this turning moment would tend to cam the detent teeth out of engagement with the teeth of the segment 50, depending upon the magnitude of the turning moment. Since the detent is yieldably urged toward the gear segment 50 by a fluid pressure piston and cylinder assemblage 54, it is apparent that as the pressure in the head end of the cylinder 55 is increased, a greater moment is required to cam the teeth of the detent out of engagement with, and by, the teeth of the segment 50, and as the pressure in the head end of the cylinder 55 is decreased, a lesser moment is required to cause disengagement of the teeth. Accordingly, therefore, by varying the pres sure in the head end of the cylinder 55, the amount of turning moment required for disengagement of the teeth and release of the saddle for free swivelling relative to the carriage 26 about the pivot 28 can be varied.

It is desirable, as hereinbefore described, to vary this pressure in the head end of the cylinder 55, and thereby the magnitude of the resisting turning moment in relation to the extension and contraction of the assemblage 29. For this purpose, there is mounted on the carriage 26 a suitable adjustable pressure control valve 59 for supplying pressure fluid to the head end of the cylinder 55. The valve 59 may be any one of a number of conventional pressure reducing valves which are readily available on the market. One example of these valves is the pressure reducing valve manufactured by Vickers, Inc., and disclosed on page 25 of Vickers Catalogue No. 500 l B, of December 1956. The valve 59 has an operating plunger 60 which, as the plunger moves inwardly and outwardly, changes the pressure which is supplied by the valve 59 to the cylinder 55. An operating cam 62 is mounted on a suitable support 61 on the slide 33 of the saddle 27 and extends longitudinally of the slideway on a slight bias to the length thereof. The cam 62 may be secured in fixed adjusted positions on the slideway and is so arranged that its operating face engages and operates the plunger 60 of the valve 59.

The slope or bias of the cam 62 is so chosen that as the assemblage 29 is extended, the pressure admitted to the head end of the cylinder 55 is increased and as the assemblage 29 is retracted, the pressure admitted to the head end of the cylinder 55 is reduced. The wiping shoe 35 and the rest of the wipe forming mechanism can withstand a force F of the predetermined maximum value Without damage. Hence, the release of the detent 51 does not become necessary until the force F exceeds the preselected maximum, regardless of the retracted or extended position.

By choosing the setting of the valve 59 and the position of the cam 62 properly, the resisting force imposed on the detent and gear segment by the cylinder 55 can be varied so that, regardless of the extended or retracted or intermediate position of the assemblage '29, it will be released for swivelling about the axis of the pivot 28 when the force component F, on the shoe laterally of the axis of the assemblage 29, exceeds a predetermined magnitude.

As mentioned, it is desirable upon release of the ram, that other portions of the mechanism be stopped. For this purpose, as will be more fully explained hereinafter, alimit switch 65 operated by a cam 66 on the detent 51 is provided. Also, a limit switch 67 having a rocker operating arm 68 engageable with the teeth of the gear.

6 segment 50 is provided for assuring the proper alignment of the teeth of the detent 5'1 and gear segment 50 and for preventing the operation of the assemblage 54 until the teeth are properly aligned. These operations are more fully described by reference to the hydraulic and wiring diagrams of Figs. 4 and 5.

Referring now to Fig. 4, the swivelling assemblage 42 for the saddle 27 is controlled by a suitable reversible flow, hydraulic control valve 70 having a plug 7 0a which is adapted, when in one position, to connect one end of the cylinder 43 to a source of pressure and the other end to a sump, concurrently; when in a second position, to reverse the connections; and, when in an intermediate position, to interconnect both ends of the cylinder 43 and connects the interconnected ends to the sump R.

The plug 70a is operated by suitable hydraulic piston and cylinder assemblages 71 to the head ends of which pressure fluid is supplied, selectively, through a suitable solenoid operated, spring return, control valve 72. The valve 72 has a plug 72a which normally is maintained in an intermediate operating position by springs 73 in which position it blocks the flow of control pressure fluid to the assemblages 71 and connects their head ends to a sump.

A throttling valve 74 is connected to the valve 70 so as to provide rapid supply of pressure fluid to either selected end of the cylinder 55 and a throttled discharge thereof to the sump R from the opposite end. The plug 72a is operated by solenoids 75 and 76. In the diagram, each solenoid operates, when energized, to move the valve plug 72a in a direction away from its own indicated position. For example, in Fig. 4, energization of the solenoid 76 moves the valve plug 72a to the left so that the connection is as indicated at the right hand end of the plug and supplies control pressure fluid to the left hand assemblage 71, setting the valve plug 70a to supply operating pressure fluid to the rod end of the assemblage 42 and to connect the head end of the cylinder 43 to the sump R, the throttling valve operating to admit pressure fluid freely to the rod end and to throttle the discharge of pressure fluid from the head end.

Pressure fluid for operating the valve 70 is supplied to the input side of the valve 70 from suitable pump P through a line 77, and is vented from the valve 70 to the sump R by a suitable line 78. A motor M is drivingly connected to the pump P. Control pressure fluid at reduced pressure is supplied to the solenoid valve 72, and all other solenoid control valves herein, from the pump P by way of a pressure reducing valve 79. Thus, by energizing and deenergizing the solenoids 75 and 76, the solenoid valve 72 can be operated to control the hydraulic piston and cylinder assemblages 71 and thereby control valve 70 of the swivelling piston and cylinde assemblage 42. l

Similarly, a hydraulic control valve 80, having a plug 80a, operated by hydraulic piston and cylinder assemblages 81, is arranged to supply pressure fluid to opposite ends, selectively, of the wipe forming cylinder 30, while connecting the opposite end'of the cylinder 30 to the sump R.

Pressure fluid is supplied to the piston and cylinder assemblages 81 by a suitable solenoid operated, spring return, control valve 82 having a plug 82a normally held in an intermediate position by springs 83 and controlled by solenoids and 86. The valve 82 is arranged to operate the valve 84 so as to urge the assemblage 29 .to the extended positon when the solenoid 85 is energized and to retracted positon when the solenoid 86 is energized, and to return the valve plug 80a to an intermediate position when both solenoids are deenergized.

In an intermediate position of the plug 80a, the head end of the cylinder 30 is connected to the sump and the rod end is hydraulically locked against extension by a check valve 87 so that the piston cannot creep forwardly due to diiferentials in pressure resulting from friction in the pipe lines.

Referring next to the swivel lock assemblage 54, the r ends of the cylinder 55 are connected to a suitable solenoid operated valve 88 having a plug 88a and a restoring spring 89, and operated by a solenoid 90. The valve 88 is operable to connect the head end of the cylinder 55 to a source of fluid pressure from the pump P and the rod end to the sump R, concurrently, when the solenoid 90 is deenergized and to reverse these connections when the solenoid 90 is energized. The fluid pressure is supplied by the pump P to the valve 88 by a line 91 through the pressure reducing valve 59 which is operated by the cam 62 and which determines the magnitude of pressure of the fluid supplied to the valve 88 in accordance with the position to which the plunger 60 is moved by the cam 62. The control of the valves is illustrated in the wiring diagram in Fig. 5.

In the form illustrated, the yieldable pressure is maintained in the head end of the cylinder of the assemblage 54 by means of the pressure reducing valve 59 which is in the nature of a variable relief valve which discharges to sump any pressure developed by the assemblage 54, in excess of that for which the valve 59 is set, due to excessive components of force F, thus assuring that the assemblage 54 can be retracted by the pressure of the teeth of the gear segment 50 on the teeth of the detent 51.

Connected across the lines L and L in series with each other from the line L to the line L are a normally open push button reset switch 100, the normally closed limit switch 65, and the control relay 101 having five normally open contacts 101a, 1010, 101d, 101 and 101g, and two normally closed contacts 101!) and 1010, all as hereinafter described. The normally open contact 101a is arranged in a holding circuit in by-passing relation to the reset switch 100 and in series with the switch 65. A time delay relay 102 of the instant closing, delayed opening type, is provided and has a contact 102a connected in a bypass circuit in by-passing relation to the switch 65. The contact 10211 is connected in series with the contact 101a. Connected in series across the lines L and L are a pilot light 103 and a normally closed contact 101b of the relay 101, so that the light lights when the relay 101 is deenergized. Connected in series across the lines L and L are a saddle traversing control and positioning switch 104 and a normally open contact 1010 of the relay 101.

For controlling the extension and contraction of the wipe forming assemblage 29, a normally open two-way switch 105, having contacts 105a and 105b is provided. The contact 105a is connected in series across the power source with the solenoid 85 of the valve 82. Between the solenoid 85 and the contact 105a, and in series therewith, is the normally open contact ;101d. The contact 10511 is connected directly across the source in series with the solenoid 86 of the valve 82.

For controlling the swivelling assemblage 42 for swivelling of the saddle, a normally open two-way switch 106, having contacts 106a and Gb is provided, the contacts being connected in circuits such that closure of contact 106a causes the assemblage 42 to swivel the saddle 27 counterclockwise (in Fig. l) and closure of the contact 1061) causes the assemblage 42 to swivel the saddle 27 in clockwise direction (in Fig. 1).

To accomplish this result, the contact 106a is connected across the source in series with the solenoid 75 of the valve 72 and the contact 106b is connected across the source in series with the solenoid 76 of the valve 72.

Connected in series between the contact 1060 and solenoid 75 is a normaly closed contact 107a of a control relay 107, and connected in series between the contact 106b and the solenoid 76 is a normally closed contact 108a of a control relay 108.

The relay 108 is connected across the source in series with the switch 67, a normaly open contact 108b being connected in series between the switch 67 and relay 108. A line 109 is connected at one terminal between the 8 contact 10811 and the relay 108, and at the other terminal between the contact 107a and solenoid 75.

Connected in parallel with the series connected contact 10812 and relay 108 and in series with each other, are the relay 107 and a normally open contact 107b of the relay 107. A line 110 is connected at one terminal between the contact 108a and the solenoid 76 and at the other terminal between the winding of the relay 107 and the contact 10712.

The solenoid of the valve 88 which controls the assemblage 54 for operating the detent 51 of the safety latching and release device is connected across the power source in series with parallel connected contacts comprising normally open contact 1080 of the relay 108, a normally open contact 1070 of the relay 107, and a normally closed contact 101:: of the relay 101. The winding of the time relay 102 is connected in series with the parallel connected contacts 1080, 1070, and 1010 and in parallel with the solenoid 90.

As mentioned, the table is driven by a motor M through suitable reduced speed transmission mechanism. Operatively interposed in this mechanism is an air applied, spring released, clutch 8 which is operated by a solenoid 113 which, when energized, operates an air valve 114, to hold the clutch engaged against the force of a spring 115, and which, when deenergized, causes the air valve to discontinue the application of clutching pressure thereby permitting release of the clutch by the spring 115. The solenoid 113 is connected across the source in series with a normally open contact 101 of the relay 101, so as to be deenergized when the relay 101 is deenergized.

If desired, a normally on brake 116 may be connected to the table drive for stopping the table, the brake being spring applied by a spring 117 and held released by air pressure under control of an air valve 118, which in turn, is under the control of a solenoid 119. The solenoid 119 operates, when it is energized, to release the brake and when it is deenergized, to permit application of the brake by the spring 117. The solenoid 119 is connected across the power source in series with a normally open contact 101g of the relay 101.

Operation Upon pressing and instantly releasing the push button of the reset switch 100, a circuit is closed through the normally closed switch 65 to the relay 101, thus energizing the relay 101. The normally open contact 101a thereupon closes and establishes a holding circuit for the relay 101 through the switch 65 and also sets up another holding circuit to be established upon closure of the contact 1020. Energization of the winding of the relay 101 opens the normally closed contact 101b, thereby deenergizing the pilot light 103, which light is to relight only when the relay 101 is again deenergized due to power failure or operation of the safety latch and release device to release the wipe forming assemblage. Energization of the relay 101 also closes the normally open contact 1010 which connects the traversing switch control 104 to the power source and renders it operable for traversing the carriage 26. Thus the pilot light 103 is extinguished and the carriage 26 is operable under the control of the control 106.

Furthermore, energization of the relay 101 closes the normally open contact 101d which sets up a circuit for controlling the solenoid 85 by the switch 105. The solenoid 86 is always under the control of the switch 105.

Operation of the switch to close the contact 105a energizes the solenoid 85 which operates the valve 82 to a position wherein it causes the hydraulic valve 80 to admit pressure fluid to the assemblage 29 so as to cause the assemblage to extend and apply the wipe forming shoe to the stock. Thus, while the relay 101 is energized, the switch 105 can be operated to apply the wiping shoe and to close the contact 105b and thereby energize the solenoid 86, thus causing it to operate the valve 82 '9 to admit pressure fluid to the assemblage 29 so as to cause the assemblage to retract the wipe shoe 35.

It is apparent that deenergization of the relay 101 causes the pilot light 103 to light, opens the contact 101e, thus preventing traversing of the carriage 26 by the control switch 104, and opens the contact 101d, thus preventing extension of the assemblage 29 by operation of the switch 105, but without preventing the assemblage 29 from being retracted by operation of the switch 105.

The switch 106 is operable to close the contacts 106a and thereby energize the solenoid 75 so that it operates the valve 72 causing it to operate the valve 70 and cause the assemblage 42 to swing the saddle in a counterclockwise direction. The switch 106 also is operable to close the contact 106b and thereby energize the solenoid 76 for operating the valves 72 and 70 to cause the assemblage 42 to swing the saddle in a clockwise direction.

These operations of the switch 106 remain possible so long as normally closed contacts 107a and 108a remain closed due to deenergization of relays 107 and 108, respectively.

The switch :106 is operable, however, to energize the solenoid 75 by closing contacts 106a even while the switch 67 and normally open contact 108b are closed.

Accordingly, the saddle 27 can be swivelled about its pivot 28 in opposite directions so long as relays 107 and 108 are deenergized, and the switch 67 is open. The switch 67 remains open so long as the detent 51 is held withdrawn from latching position by the assemblage 54 or by the misalignment of the teeth which causes the switch 67 to be held open by the rocker arm 68.

When, due to misalignment, the switch 67 is closed then by closing contact 106b the relay 107 is energized to set up a holding circuit through the switch 67 by closure of its normally open contact 107b. Concurrently, the relay 107 opens normally closed contact 107a, and due to the connecting line 110, energizes solenoid 76, which causes the assemblage 42 to swivel the saddle 27 clockwise. Thereupon, as soon as the teeth are aligned, rocker 68 drops between teeth of the gear segment 50 and the switch 67 opens, dropping out contact 1071) to reopen the holding circuit and causing contact 107a to reclose, providing the assemblage 54 is urging the detent 51 toward latching position.

The switch 67, being in by-passing relation to the switch 106, is operable, when closed, after the holding circuit through contact 10711 is established, to align the teeth when the switch 106 is in the off position, and by virtue of opening the contact 107a, remains operable even through the switch is set for swivelling the saddle counterclockwise in Fig. 1.

It is to be noted that the solenoid 90 is energized through the normally closed contact 101e and, when so energized, renders the assemblage 54 operative to retract the detent, leaving the saddle free to swing about the pivot 28 whenever the relay 101 is deenergized. Accordingly, whenever the teeth are caused to separate, due to an excessive force component F, applied to the shoe, the cam 66 opens the switch 65, deenergizing the relay 1011, causing the contact 101e to close and energize the solenoid 90, thus releasing the detent 51 from the gear segment 50. At the same time, due to opening the switch 65, the contact 101 drops out, deenergizing the solenoid 113 so that the air valve 114 releases pressure on the clutch and the clutch is disengaged by the spring 115. Concurrently, the contact 101g drops out, thus deenergizing the solenoid 119 so that the air valve 118 releases the brake releasing pressure and the spring 117 thereon applies the brake 116, stopping the table 3.

So long as the switch 65 remains open, as when the teeth are misaligned, or the detent is retracted, contact 101e remains closed and energizes the solenoid 90 to hold the detent retracted. Also, it maintains energization of the time delay relay 102. However, circuits for energizing the solenoid 90 and relay 102 can be estab- 10 lished byclosing either contact 1070 or 1080 even though the switch 65 is closed and relay 10 1 is energized. Contact 107c can be closed by operating the saddle swivelling switch 106 to close contact 106b when relay 108 is deenergized and contacts 108a closed thereby.

If, with the switch 65 open, it is desired to swivel the assemblage 29, this can be done as the closed contact 101e maintains energization of the solenoid 90, causing the detent to remain retracted.

If the switch 65 is closed, and relay 101 is energized, contact 101e opens, and the detent 51 engages. However, if the contact 106a is closed, relay .108 is energized through the normally closed contact 107a, closing contact 1080 to energize the solenoid and retract the detent 51, and establishing a holding circuit for the relay 108 for maintaining the contact 1080 closed. If the contact 106b is closed, the relay 107 is energized through the normally closed contact 108a, closing the contact 1070 to energize the solenoid 90 and retract the detent 51, and establishing a holding circuit through the contact 107b.

Thus operation of the switch 106, even when the switch 65 is closed, causes swivelling of the wipe forming assemblage. When the switch 106 is returned to off position, if the switch 65 is open, the detent remains disengaged.

To reengage the detent, with the switch 106 in off position, the reset button must be operated to close switch 100, thereby energizing the relay 101 through the contact 102a which is held closed because of the circuit through 1012 and the relay 102. Energization of the relay 101 opens the contact 101e and thereby deenergizes the solenoid 90. I

If, while the saddle is locked, an excessive force component F is applied, the detent is forced by the teeth out of engagement, thereby causing switch 65 to open and deenergize relay 101, thereby opening contact 101 to declutch the table drive and opening 101g to allow the brake 116 to be applied, closing 101e to energize the solenoid 90 and hold the detent retracted, and thereby releasing the wipe forming assemblage for free swivelling, whereby the wipe forming assemblage is prevented from damage by excessive force components F.

In the form illustrated, the invention has been described as applied to a machine in which the frame is stationary on the floor, and the table is rotated. It is apparent, however, that the same invention may equally be embodied in a machine in which the relative rotation of the die supporting table and the stretch forming assembly is effected by holding the table stationary and rotating the frame 1, the relative rotation of the two being important.

Furthermore, in the present description, the machine has been described as though operating with a table hav ing an upright axis. This is for convenience in defining the relative positions of the parts, as obviously the machine can be operated equally as well were it disposed with the table axle horizontal or in some other position than upright, and the terms upright and horizontal, as used in the description and in the claims, are not meant to limit the structure to such terms as absolute but only to describe the relative position of the parts.

Having thus described my invention, I claim:

1. In a metal forming machine, a table, a side face die mounted on one face of the table, clamping means for clamping a length of stock at one portion in fixed relation to the die, a metal forming tool, a wipe forming assemblage connected to the tool and extensible and contractible in directions generally toward and away from the die face for maintaining the tool in operative relation to the die face, supporting means supporting the table and assemblage for rotation relative to each other about a predetermined axis normal to said face of the table for causing the tool to travel along the die face, power means to cause said relative rotation, yieldable pressure means yieldably urging the assemblage to extended condition, complementary latch means including latch members operatively 1 1 connected to the assemblage and to the supporting means, respectively, and movable into and out of latching relation with respect to each other, connecting means conmeeting the assemblage to the supporting means for bodily movement of the assemblage relative to the supporting means into an operative position wherein the assemblage cah maintain the tool in engagement with the die and out of said operative position, respectively, yieldable pressure applying means connected to the latch means and yieldably holding the latch members in latching relation with each other when the assemblage is in said operative position, said latching means including means to cause movement of the members out of latching relation against the force of said yieldable pressure applying means consequent upon application of a predetermined maximum component of force on the assemblage in a direction urging the assemblage out of said operative position, a variable pressure device operatively connected to said yieldable pressure applying means for varying the pressure with which the members are held in latching engagement by the yieldable pressure applying means, and control means operatively interconnecting the device and assemblage for operating the device, in relation to the extension and retraction of the assemblage, so as to increase the pressure engagement of the members upon extension of the assemblage and to decrease the pressure engagement upon retraction of the assemblage.

2. The structure according to claim 1 wherein said means included in the latching means are interengaging shoulders on the members which shoulders lie in a plane biased to the line of the forces applied to them by said maximum component of force.

3. The structure according to claim 1 wherein the yieldable pressure applying means includes a fluid pressure operable piston and cylinder assembly, the variable pressure device includes a fluid pressure adjusting valve and pump means for supplying operative fluid, under pressure, to the assembly through the valve.

4. The structure according to claim 3 wherein said wipe forming assemblage includes a piston member and a cylinder member, said device being connected in fixed position relative to one of the members, and the control means being connected in fixed position relative to the other of the members.

5. The structure according to claim 4 wherein said de vice includes a movable cam operable control element,

and the control means comprises a cam operatively engaged with the element.

6. The structure according to claim 5 wherein said cam has an elongated operating face extending generally endwise of the wipe fonning assemblage and spaced from and on a bias to the axis of the piston member.

7. The structure according to claim 1 wherein the connecting means is a pivot parallel to said predetermined axis, and said assemblage is movable bodily by swinging it about said pivot.

8. The structure according to claim 7 wherein the latch member connected to the assemblage is an external gear segment coaxial with said pivot and the latch member connected to the supporting means is a detent having teeth complementary to the teeth of the gear segment.

9. The structure according to claim 1 wherein the connecting means connect the assemblage to the supporting means for bodily movement of the assemblage to a plurality of operating positions and said latch members are engageable with each other in each of said operating positions of the assemblage for yieldably latching the assemblage in each of said operating positions, selectively.

10. The structure according to claim 1 including additionally additional control means operatively connected to the latch means and operated thereby, when the latch means are moved a predetermined distance in the released direction by said component of force, for causing the yieldable pressure applying means to retract the latch means from latching position and to retain the latch means out of latching position.

11. The structure according to claim 1 including additionally alignment control means which are operatively connected to the latch means and are operated thereby, when the latch means are released, to constrain the latch means from moving toward latching position when the latch members are misaligned with respect to each other.

12. The structure according to claim 1 and including additionally table control means operatively connected to the latch means so as to be rendered operative when the latch means are moved a predetermined distance in the releasing direction relative to each other, to stop the relative rotation of the table and wipe forming assemblage about said predetermined axis.

References'Cited in the file of this patent UNITED STATES PATENTS 2,274,856 Wisckol Mar. 3, 1942

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