US2913784A - Hold-down device for machines for rotating cylindrical articles - Google Patents

Description

N .24, 95 J; 1.. COOPER ErAL 2,913,784

[ HOLD-DOWN DEVICE FOR MACHINES FDR ROTATING CYLINDRICAL ARTICLES Filed Jan. 17, 1957 '6 Sheets-Sheet 1 .v INVENTORS JACOB L. COOPER KENNETH R. DAN/EL JAMES 6. LOWER) ATTORNEYS Nov. 24, 1959 J. L. COOPER A 8 HOLD-DOWN DEVICE FOR MACHINES FOR ROTATING CYLINDRICAL ARTICLES Filed Jan. 17, 1957 6 Sheets-sheaf 2 INVENTORS JACOB 1.. 000, 50 KENNETH R. mam/1. JAMES 0. LOWER) ATTORNEYS BY/M/ Nov. 24, 1959 J. L. CO0PER ETAL HOLD-DOWN DEVICE FOR MACHINES FOR ROTATING CYLINDRICAL ARTICLES 6 sheets sheet 3 Filed Jan, 17,1957

INVENTORS JACOB L. COOPER KENNETH R. DAN/EL JAMES 6. LOWE RY ATTORNEYS J. 1.. COOPER ET AL 2,913,784

HOLD-DOWN DEVICE FOR MACHINES FOR ROTATING CYLINDRICAL ARTICLES 6 Sheets-Sheet 4 M ORLY MEIR W 00 L 0 E s O E GM M M hnu 2 v o 1 1 n 9% JHH I k vu m n mm m 2 mm M M mm un r W wk R k R 0 m mo R 0 mm o L Q. T v I I Q o o Y mm Q 4 Q v\ an Q Mm mu 1 mw I N l l .ll ww IIlIHkMTI & Q Nu T llll KVTIQA \w R Q m mm 3 .Q\ G mklmxx 8 mm v T m wk w .i. Q m l Nov. 24,1959

Filed Jan. 17. 1957 BY I M MZZZK ATTORNEYS 9 J. COOPER ETAL HOLD-DOWN DEVICE FOR MACHINES FOR ROTATING CYLINDRICAL ARTICLES Filed Jan. 17. 1957 6 Sheets-Sheet 5 INVENTORS 7 JACOB L. COOPER KENNETH R DAN/EL JAMES O. LOWER) finer-n4, MM

ATTORNEY 5 Nov. 24, 1959 L. COOPER ETAL I 2,913,784

HOLD-DOWN DEVICE FOR MACHINES FOR ROTATING CYLINDRICAL ARTICLES Filed Jan. 17. 1957 Y a Sheets-Sheet 6 AIR HYDRAULIC 00 FLUID FREE- FLOW RESTRIOTEDFLOW F R E 5- FLO VI RESTRIGTED+F LOW INVENTORS JACOB L. COOPER KENNETH R. DAN/E L JAMES 6. LOWER) ATTORNEYS United States Pate t e HOLD-DOWN DEVICE FOR MACHINES FOR ROTATING CYLINDRICAL ARTICLES Application January 17, 1957, Serial No. 634,720

Claims. (Cl. 22-65) This invention relates to apparatus for rotating at relatively high speeds generally cylindrical articles of substantial mass, such as centrifugal'casting molds, metal pipes and the like, and more particularly concerns a safety device for restraining a spinning article against accidental ejectment from the apparatus while it is being rotated. j

Inasmuch as the device of the present invention is especially well adapted for use with the high speed spinning machines employed for rotating molds and pipes in the manufacture of centrifugallycast metal pipe, the following disclosure will be directed primarily to this particular application of the inventive t concept. By so doing, however, it is not intended to limit the scope of the invention to mechanism for rotating pipe casting molds or. pipes, because it will be evident that the apparatus is useful wherever means are needed to hold a rotatable body down on rollers or similar spinning elements. r j a The principal object of the invention is to provide an improved restraining mechanism for preventing a rapidly spinning object from accidentally jumping off the rollers or, other members by which it is being rotated.w

Another object is the. provision of a hold-down device of the character described which is readily adjustable for use with centrifugal casting molds, pipes and other cylindrical'articles of different diameters.

A further object of the invention is to provide a mold or pipe spinningmachine with a hold-down mechanism of novel construction the operation of which is interlocked with that ofthe means whereby the molds or pipes are delivered to and discharged from the rotating mechanism..

Still another object is the provision of unique means for moving the restraining elements of a hold-down device of the character described into an operative posi tion wherein they obstruct bodily movement of an article while it is. spinning and then returning them to an inoperative position wherein they do not interfere with delivery and discharge of articles to and from the spinning mechanism. 7

These and other objects, including the provision of a hold-down device which is normally out of contact with the rotating article, will appear more fully upon consideration of the detailed description of the embodiment of the invention which follows. In this connection, although only one specific form of apparatus is described and illustrated in the accompanying drawings, it is to be expressly understood that these drawings are for purposes of illustration only and are not to be construed as defining the limits of the invention, for which latter purpose reference should be had to the appended claims.

In the drawings, wherein for illustrative purposes the articles to be rotated are shown as molds or flasks of the type commonly used for centrifugally casting bell and spigot cast metal pipe, and wherein like reference characters indicate like parts" throughout the several views:

ice

Fig. 1 is a plan view of a known type of mold rotating apparatus embodying one form of hold-down mechanism according to the present invention, certain parts being broken away or shown in section along the line 1-1 in Fig. 4 and the central portion of the mold on the spinning rollers being omitted so as to more clearly illustrate certain structural features of the machine;

Fig. 2 is a side view of the apparatus of Fig. 1, partially in section along the line 22 in Fig. l; a

Fig. 3 is a fragmentary plan view of part of the hold-down mechanism which is broken away in Fig. 1;

Fig. 4 is across section taken substantially on line 44 in'Fig. 1, showing the means by which molds are delivered to and discharged from the rotating mechanism, the parts being shown in the positions occupied when one mold is being discharged from and another mold is being delivered to the machine, and when the hold-down mechanism is set to accommodate a mold of relatively large diameter;

Fig. 5 is a cross-sectional view similar to Fig. 4, but showing the parts in the positions occupied when a mold is being rotated;

Fig. 6 is a fragmentary cross section taken substantially on line 6-6 in Fig. 1, showing the means by which the hold-down mechanism may be adjusted to accommodate molds of different diameters;

Fig. 7 is an enlarged view similar to Figs. 4- and 5, but omitting the mold delivery and discharge means and indicating diagrammatically the relative positions of the elements of the hold-down mechanism when said mechanism is adjusted to accommodate molds for casting six different sizes of pipe ranging from 12" to 24 in diameter; and

Fig. 8 is a schematic diagram of the control system by which operation of. the hold-down mechanism is interlocked with that of the mold delivery and discharge means.

As stated above, the hold-down device of the presen of a mold lining machine of the character disclosed in the copending application of Kenneth R. Daniel et al., Serial No. 555,934, filed December 28, 1955, now Patent No. 2,873,716.

As shown in Figs. 1-5, the mold rotating mechanism comprises a plurality of spinning rollers 11 adapted to support a substantially cylindrical article, such as a centrifugal casting mold 12, in a horizontal position and to rapidly rotate the mold about its axis while any desired operation is being performed, such as lining the mold or casting a pipe therein. The rollers 11 are mounted in two sets on shafts 13 and 14 which extend parallel to the axis of the mold and are journaled in bearings 15 mounted on a stationary base 16 suitably fixed to the machine foundation. In the embodiment illustrated, shaft 13 is adapted to be driven in any suitable manner, as by a variable speed motor (not shown), while shaft 14 is an idler, the rollers on the latter shaft deriving their rotation from the mold 12 which in turn is frictionally driven by the rollers on shaft 13. Shaft 13 is also provided with a flanged wheel 17 which receives the guide flange 18 of mold 12 and holds the mold against movement in an axial direction during its rotation.

In order to properly control the delivery and discharge of molds to and from spinning rollers 11, the mold rotating mechanism includes a pair of parallel, axially spaced detent-guide arms 19 which control the delivery 2,913,784 Patented Nov. 24, 1959 kickout arms the primary purpose of which is to eject the molds from the machine after the lining, casting or other operation has been completed.

As indicated in Figs. 1, 4 and 5, kickout arms 20 are fixed to the ends of a torque tube 21 which is mounted for oscillatory movement about a fixed axis parallel to the axes of spinning roller shafts 13 and 14 at a position beneath the ends of mold run rails 22 at the discharge side of the machine. The upper surface of each kickout arm 20 is of bent shape, having a portion 23 which is substantially tangent to the upper surface of torque tube 21 and a second portion 24 which is inclined downwardly relative to radially extending portion 23 and terminates in an upwardly extending pointed end portion 25. As shown in Fig. 5, the pointed end portions 25 project slightly beyond the vertical axial plane of mold 12, toward the side of the machine from which the molds are loaded, when the mold is in spinning position on rollers 11.

Each of detent-guide arms 19 is provided with a clevisshaped inner end pivotally connected to the free end of the associated kickout arm 20 by a pin 26 at a point just below the junction between pointed end portion 25 and inclined portion 24 of the kickout arm, and is also of irregular shape. As shown best in Fig. 4, the upper surface of each detent-guide arm 19 is bent at substantially the same angle as the upper surface of kickout arm 20, having a portion 27 at. the outer end of the arm which is inclined downwardly with respect to the portion 28 at the inner end of said arm. The bottom edge of each detent-guide arm 19 rests on a flanged roller 29 rotatably mounted in a bearing bracket 30 fixed to base 16. Rollers 29 engage the bottom edges of detentguide arms 19 at points substantially directly beneath the junctions between surfaces 27 and 28, and support said arms in a position such that said junctions lie in approximately the same plane as the rolling surfaces of mold run rails 22. The two detent-guide arms 19 are interconnected by a tie tube or rod 31 at points intermediate the axes of flanged rollers 29 and the inner ends of said arms where they are pivoted to kickout arms 20, tie tube 31 extending parallel to torque tube 21.

Fixed to torque tube 21 intermediate its ends is a radially extending operating arm 32 which lies in substantially the same plane as kickout arms 20 and is pivotally connected at its inner end to the upper end of the piston 33 of a hydraulic cylinder 34. Cylinder 34 extends downwardly through a central opening in base 16 and is provided at its lower end with a base cap 35 which is pivotally connected to a supporting bracket 36 fixed to the machine foundation.

When a mold is in rotating position on spinning rollers 11 (see Fig. 5), piston 33 of hydraulic cylinder 34 is in its fully retracted position and detent-guide arms 19 and kickout arms 20 form a wide V with their upper surfaces completely out of contact with the lower surface of mold 12. At this time, the outer ends of detentguide arms 19 project upwardly above the rolling surfaces of rails 22 in such position as to prevent the next mold on the delivery side of the machine from entering the mold rotating mechanism.

Upon completion of the lining, casting or other operation during which rotation of the mold has been effected by rollers 11, the mold is ejected or discharged from the machine by so admitting hydraulic fluid to cylinder 34 as to raise piston 33 to the uppermost position permitted by adjustable stop nuts 37 threaded on rods 38 which depend from the upper end of said piston and pass through openings in the cylinder head. The upward motion of piston 33 is transmitted by operating arm 32 to torque tube 21 and results in a counterclockwise rotation of the latter and movement of kickout arms 20 to the position indicated in Fig. 4. As kickout arms 20 are raised from the position shown in Fig. 5, their pointed end portions 25 and inclined surfaces 27 come into conpersonnel.

tact with the surface of mold 12 at points on opposite sides of the vertical axial plane thereof, raise the mold, and then, as inclined surfaces 27 rise above the level of the rolling surfaces of rails 22, roll the mold off the kickout arms and onto said rails.

Due to the pivoted connection between kickout arms 20 and detent-guide arms 19, elevation of the former also raises the inner portions of the latter to a substantially horizontal position, level with rails 22, and lowers the outer ends thereof below the rolling surfaces of the rails. The next mold in line may then roll into the machine to the position indicated in broken lines in Fig. 4, where the pointed ends of kickout arms 20 hold the mold until it is lowered onto'rollers 11 when hydraulic cylinder 34 is exhausted and piston 33 returns to the retracted position shown in Fig. 5. As the inner ends of detent-guide arms 19 are raised by virtue of their pinned connection with the ends of kickout arms 20, rollers 29 permit arms 19 to adjust their positions accordingly, forming in effect movable fulcrums for said arms.

As will be explained hereinafter in connection with the control system shown diagrammatically in Fig. 8, retraction of piston 33 is accomplished automatically as the result of actuation of a kickout down limit switch S1 which is positioned alongside one of rails 22 closely adjacent the end of said rail from which the molds roll into the spinning machine, and the operating lever of which is depressed by the molds as they roll thereover.

Although the occurrence is rare, it sometimes happens that a mold begins to bounce as it is rotated by the spinning mechanism and may be accidentally thrown out of the machine with consequent damage to the mold or other machinery and possible personal injury to plant In order to prevent such accidents, means must be provided for positively preventing the mold from leaving the machine during the spinning operation. The present invention provides a safety mechanism for this purpose which is characterized by its adjustability to accommodate molds of different sizes, by its adaptability for automatic, interlocked operation in cooperation with the spinning mechanism, and by the absence of contact with the rotating mold during normal operation.

In the embodiment illustrated, the safety mechanism comprises a pair of angular hold-down arms 39 located at the discharge side of the machine which are movable into and out of mold restraining position by an actuating assembly consisting of a torque tube 40, a pair of lifting arms 41 fixed to the ends of tube 40, and an actuating arm 42 also fixed to tube 40 intermediate its ends. The path of movement of hold-down arms 39 is established by a second assembly consisting of a pivot arm 43, a pivot tube 44 to which arm 43 is fixed and which extends between hold-down arms 39, and a pivot shaft 45 which extends axially through and is keyed to tube 44 and on the ends of which the hold-down arms are pivotally mounted. The free end of arm 43 is bifurcated and pivotally connected to the upper end of a vertically movable pivot member 46 the position of which is adjustable so as to vary the height of the point about which the oscillatory movement of hold-down arms 39 takes place upon actuation by the means next to be described.

As is shown best in Figs. 1 and 2, the assembly of torque tube 40, lifting arms 41 and actuating arm 42 is pivotally mounted on a pivot plate 47 which is fixed to one of the supporting I-beams 48 of the machine base 16 in a vertical plane slightly offset from that of torque tube 21 of the kickout mechanism. To this end, pivot plate 47 is provided adjacent its ends with a pair of horizontally projecting lugs 49 carrying pivot pins 50 on which are journaled the ends of lifting arms 41. In the embodiment illustrated, each of lifting arms 41 is formed of a piar of parallel, spaced apart pieces united by transversely extending spacers 51 which are welded thereto intermediate the ends of the arms so as to provide bifurcated arm ends to receive pivot lugs 49. At the opposite extremities .of lifting arms 41, the bifurcated ends thereof receive the lower ends of hold-dowmarms 39 which are pivotally connected thereto by pivot pins 52.

Actuating arm 42, which is also of bifurcated construction, is welded or otherwise fixed to torque tube 40 in substantially the same plane as lifting arms 41, and is pivotally connected at its free end to the upper end of the piston 53 of a hydraulic cylinder 54 which provides the actuating force of the holddown mechanism. Like cylinder 34 of the rotating mechanism, cylinder 54 .is mounted in a generally vertical position, being provided at its lower end with a base cap 55 which is pivotally connected to a supporting bracket 56 fixed to the machine foundation, and is adapted to raise piston 53 from the retracted position shown in Fig. 4 to the elevated position of Fig. which is established by adjustable stop nuts 57 threaded on rods 58 depending from the upper end of said piston and passing through openings in the head of cylinder 54. The flow of hydraulic fluid to and from cylinder 54 is controlled automatically in predetermined relationship with the flow of fluid to cylinder 34 by the system illustrated in Fig. 8 as hereinafter described.

In order to guide the hold-down arms in the proper path and to the proper elevated position to accommodate the size of mold being rotated, arms 39 are pivotally journaled or fulcrumedon the ends of pivot shaft 45, and the end of pivot arm 43 opposite its connection to pivot tube 44 is journaled on the ends of a pin 59 which is carried by and fixed to the upper end of the vertically adjustable pivot member 46. Pivot arm 43 and lifting arms 41 thus form with the lower portions of hold-down arms 39 a variable motion linkage having one permanently fixed pivot defined by pivot pins 50 and a second normally stationary, but vertically adjustable pivot provided by pin 59.

The means by which the vertical positions of pivot member 46 and pin 59 may be adjusted are shown best in Fig. 6. In the form there illustrated, pivot member 46 is slidably supported in a guide member 60 mounted on pivot plate 47 intermediate the ends thereof, and is provided at its lower end with a vertically extending, internally threaded bore 61 into which extends the upper threaded end of a screw shaft 62. The lower portion of shaft 62 is journaled in a suitable thrust bearing 63 and is connected by a coupling 64 of any suitable type to the output shaft 65 of a reducing gear drive 66. The input shaft 67 of reducer 66 is drivably connected by a coupling 68 to a torque motor 69 which is reversible in operation and adapted to be manually controlled by the operator of the machine. The reducing gear drive 66 and the threaded connection between shaft 62 and bore 61 of pivot member 46 are so constructed that, when torque motor 69 is energized to rotate screw shaft 62 in the desired direction, pivot member 46 is either raised or lowered so as to vary the vertical position of pivot pin 59 which forms a center about which hold-down arms 39 move in space when raised and lowered by'lifting arms 41 upon operation of actuating cylinder 54.

In order that the machine operator may readily set the hold-down mechanism to accommodate a mold of any specific diameter, means are provided by which the operator may quickly and accurately position pivot member 46 at the proper elevation. In the embodiment illustrated, adjustment of the vertical position of pivot member 46 is accomplished by the use of a stepped bar 70 which is longitudinally slidable on flanged guide rollers 71 through a vertically elongated slot 72 formed in the upper portion of pivot member 46 intermediate pivot pin 59 and internally threaded bore 61. Rollers 71 are journaled on stub shafts 73 which are suitably mounted in supporting brackets 74 carried by pivot plate 47. The steps on bar 70 are formed on the lower surface thereof at elevations corresponding to the different diameters ofmolds which the machine is adapted to rotate, and are provided with replaceable shims 75 which permit accurate adjustment 6 of the mechanism. The bottom surfaces of shims 75 form. stops against which the base of slot 72 in pivot member 46 is adapted to abut when the pivot member has been elevated to the proper position.

Bar 70 may be adjusted to bring into position in slot 72 the proper step for the size of mold to be rotated by first'energizing torque motor 69 so as to rotate screw shaft 62 in a counterclockwise direction andmove pivot member 46 to its lowermost position, at which time the base of slot 72 is below the shim 75 of the step corresponding to the smallest mold to be accommodated, e.g., a 12" mold in the embodiment illustrated. Stepped bar 70 may then be moved in either direction on guide rollers 71 by means of a hydraulic adjusting cylinder 76v having its piston 77 connected to one end of bar 70. Operation of cylinder 76 and piston 77 may be controlled manually by the operator of the machine in any suitable manner, as by means of a push button operated, solenoid air valve and a four-way hydraulic valve for controlling the flow of hydraulic fluid to cylinder 76, which controls have been omitted from the drawings in the interestv of simplicity. In order to indicate which step of bar 70 is positioned in slot 72 at any particular time, the bar may be provided with a horizontally extending arm 78 having a pointer at one end which registers with an indicator plate 79 carrying index marks corresponding to the various steps of bar 70 and the sizes of molds which the machine is adapted to handle, and suitably mounted on the machine base 16 in a position where it can be readily ob-. served by the operator.

When stepped bar 70 has been moved to a position corresponding to the size of mold to be rotated, torque motor 69 is again manually energized by the operator so as to rotate screw shaft 62 in a clockwise direction and raise pivot member 46 until the base of slot 72 comes into abutment with shim-75. of the step then located in the slot. With a torque motor and reducing gear drive of suitable character, the operator can determine when the pivot member has reached the desired elevation by simply watching the coupling 68 between the motor and reducing gear and opening the motor circuit when rotation of the coupling stops.

After pivot member 46 has been adjusted to the proper position in the manner above described, so as to set the hold-down mechanism to accommodate a mold of the selected diameter, hold-down arms 39 may be raised to their up or mold restraining position by supplying fluid to the bottom end of actuating cylinder 54 and thereby elevating piston 53 to the uppermost position permitted by stop nuts 57. The vertical movement of piston 53 rotates the integral assembly of actuating arm 42, torque tube 40 and lifting arms 41 about the permanently stationary pivotal axis of the torque tube and lifts the lower ends of hold-down arms 39 through a fixed are about said axis as center. However, the path of movement of the portions of hold-down arms 39 above their lower ends, and the final up position of the upper ends of said arms, are determined by the elevation of adjustable pivot member 46 and pivot pin 59 which provide the second normally stationary pivot of the arm moving linkage and establish the center of the arc through which move the pivotal connections between arms 39 and pivot shaft 45.

When it is desired to discharge the mold from the: machine, the flow of hydraulic fluid to actuating cylinder 54 is reversed so as to move piston 53 downwardly to the bottom of its stroke and thereby return the holddown arms 39 to the retracted or inoperative position illustrated in Fig. 4. The mold may then be ejected from the rotating mechanism by actuation of kickout cylinder 34 in the manner previously described.

As indicated in Figs. 1, 4, 5 and 7, hold-down arms. 39 are T-sh'aped in cross section, with the transversely extending portion of the T forming the lower or mold obstructing surface of the arms, and are so'formed that the portions above their connections to pivot shaft 45 are inclined at an angle of approximately 45 with respect to their lower portions, while their upper or tip ends have an additional inclination of approximately 22 /z in the same direction. The shape of hold-down arms 39, the dimensions of the linkage by which they are raised and lowered, and the adjustable positions of the movable pivot provided by member 46 and pin 59 are so designed that, when the hold-down arms are in their retracted or inoperative positions, their upper ends lie below the rolling surfaces of mold run rails 22 so as not to obstruct the path of discharge of molds from the machine, whereas in their elevated or operative positions, they obstruct bodily movement of a rotating mold both upwardly and laterally in the direction of discharge, but at the same time provide a clearance of approximately 4" between the upper surface of the mold and the overlying upper ends of the arms. In this connection, it should be noted that the stroke of piston 53 of actuating cylinder 54 is constant for all sizes of molds, so that actuating arm 42, torque tube 40, lifting arms 41 and the lower ends of hold-down arms 39 rotate through a constant arc, although the upper portions of arms 39 move in a different path for each different size of mold due to the adjustment of pivot member 46.

Although it is obvious that the hold-down mechanism of the present invention may be manually controlled independently of the rotating mechanism, the hydraulic actuating means of the two mechanisms are preferably interlocked and electrically controlled by a suitable system of switches and valves, such as that'schematically illustrated in Fig. 8.

As shown, the flow of hydraulic fluid to and from kickout actuating cylinder 34 and hold-down actuating cylinder 54 is controlled by a four-way two-position valve 80 which may be operated pneumatically by a solenoid actuated pilot valve 81. The hydraulic connections between valve 80 and cylinders 34 and 54 are so arranged that, when the piston 33 of kickout cylinder 34 is in the extended position illustrated in Fig. 4, which so positions detent-guide arms 19 and kickout arms 20 as to permit a mold 12 to roll from rails 22 into the rotating mechanism, piston 53 of hold-down cylinder 54 is retracted so as to lower hold-down arms 39 beneath rails 22 at the discharge side of the rotating mechanism and permit the previously rotated mold to leave the machine. When the parts are so positioned, the solenoid or pilot valve 81 is energized from a suitable power source through normally closed kickout down limit switch S1 and a second switch S2 which may be operated either manually or automatically at predetermined times in the cycle of the apparatus of which the rotating mechanism is a part. For example, in the case of a mold lining machine of the character disclosed in the previously mentioned Danel et al. application, Serial No. 555,934, the

switch S2 may be operated automatically by the movable car on which the lining trough is carried.

As a new mold enters the rotating mechanism, it rolls over and opens kickout down switch S1 to deenergize the solenoid of pneumatic pilot valve 81 which in turn actuates the four-way valve 89 so as to reverse the flow of hydraulic fluid to cylinders 34 and 54, thereby lowering piston 33, detent-guide arms 19 and kickout arms 20 and raising piston 53 and hold-down arms 39 to the positions shown in Fig. 5. As detent-guide arms 19 and kickout arms 20 are lowered and deliver the mold onto spinning rollers 11, hold-down arms 39 are moved into their up position wherein they positively restrain the mold against accidental ejectment from the spining mechanism.

After the mold has been rotated for the desired length of time, switch S2 is closed either manually or automatically to again energize the solenoid of pneumatic pilot valve 81 and return hydraulic valve 80 to its original position wherein fluid is so supplied to cylinders 34 and 54 as to retract piston 53 of hold-down actuating cylinder 54, thereby lowering hold-down arms 39 to their down position, and to simultaneously extend piston 33 of kickout cylinder 34, thereby elevating detentguide arms 19 and kickout arms 20 to eject the mold from the rotating mechanism.

Although the electrical circuit for controlling the solenoid of pilot valve 81 through switches S1 and S2 has not been shown in detail in Fig. 8, it will be understood that any suitable means may be employed for maintaining the solenoid deenergized throughout the time that a mold is being lowered onto and rotated by spinning rollers 11, but otherwise energized as long as the machine is in use.

In order to avoid interference between hold-down arms 39 and molds 12 as the latter are lowered onto and raised from spinning rollers 11, it is necessary to carefully control the relative speeds of movement of the pistons 33 and 53 of cylinders 34 and 54, respectively. For example, the speed of the upward or extending movement of piston 53 of hold-down actuating cylinder 54 must be slowed relative to the downward or retracting movement of piston 33 of kickout cylinder 34 sufliciently to insure that the mold has been lowered onto spinning rollers 11 before hold-down arms 39 reached their up position. Furthermore, the speed of the upward or extending movement of kickout piston 33 must be slowed relative to the downward or retracting movement of hold-down piston 53 sufficiently to insure that hold-down arms 39 are retracted below the rolling surfaces of mold run rails 22 before the mold is discharged onto said rails by kickout arms 20. To this end, the fluid line leading to the upper end of each of cylinders 34 and 54 is provided with a known form of adjustable flow control valve 82 which is so constructed as to adjustably restrict the velocity of flow away from the cylinder, but to allow fluid to flow relatively freely'toward the cylinder. Such valves are commonly provided with adjustable means which restrict the cross-sectional area of the fluid passage for flow in one direction and with a check or poppet valve arrangement which permits flow in the opposite direction to by-pass the restricted area.

If desired, a similar flow control valve 32 may be installed in the line leading to the bottom of cylinder 34 so that the speed of the downward or retracting movement of kickout plunger 33 maybe slowed sutliciently to prevent the mold from bumping spinning rollers 11 with excessive force as it is lowered.

The fluid supply line leading to the bottom of holddown cylinder 54 is not provided with an adjustable flow control valve of the character above described, but preferably includes a normally open globe valve 83 which can be closed to permit lowering or retraction of piston 33 of kickout cylinder 34 without raising or extending piston 53 of hold-down cylinder 54, so as to facilitate maintenance and repair work on the kickout and hold-down mechanisms.

Although only one specific form of apparatus embodying the invention has been described and illustrated in the accompanying drawings, it will be obvious that the invention is not limited either to the particular structure shown or to use in the type of machine disclosed, but is capable of a variety of mechanical embodiments. Various changes, which will now suggest themselves to those skilled in the art, may be made in the form, details of construction and arrangement of the mechanical parts, and in the electrical and fluid pressure means used for controlling the various elements of the apparatus, without departing from the spirit of the invention.

Reference is therefore to be had to the appended claims for a definition of the limits of the invention.

What is claimed is:

1. In a machine for rotating a generally cylindrical article about its axis while said axis is in a substantially horizontal position, a safety device for preventing accidental ejectment of said article from the machine comprising a restraining member having an upper end adapted to be positioned adjacent to the surface of said article to obstruct bodily movement of said article while it is being rotated, means for moving said restraining member into and out of obstructing position including a linkage having one arm rotatable about a permanently fixed pivot and operatively connected to the lower end of said restraining member and a second arm rotatable about a movable pivot and operatively connected to said restraining member at a point intermediate its ends, means for applying an actuating force to said first arm, and means for varying the position of the movable pivot of said second arm so as to adjust the obstructing position of the upper end of said restraining member for cooperation with articles of different diameters.

2. In a machine for rotating a generally cylindrical article about its axis while said axis is in a substantially horizontal position, a safety device for preventing accidental ejectment of said article from the machine comprising a restraining member adapted to be positioned adjacent to the surface of said article to obstruct bodily movement of said article while it is being rotated, means for moving said restraining member into and out of obstructing position including a linkage having one arm rotatable about a permanently fixed pivot and second arm rotatable about a movable pivot, means for applying an actuating force to said first arm, and means for varying the position of the movable pivot of said second arm so as to adjust the obstructing position of said restraining member for cooperation with articles of different diameters, said last named means including a movable member on which said second arm is pivoted, means for moving said movable member relative to the fixed pivot of said first arm, a stop member having a stepped surface adapted to engage and stop the movement of said movable member, and means for adjusting said stop member to bring diiferent steps into position to engage said movable member and thereby vary the position at which the movement of said movable member is stopped.

3. In a machine for rotating a generally cylindrical article about its axis while said axis is in a substantially horizontal position of the type wherein the article is delivered to and from the rotating mechanism by movement along a substantially horizontal path, a safety device for preventing accidental ejectment of said article from the machine comprising a restraining arm having a portion adapted to be positioned above the upper surface of said article to obstruct bodily movement of said article while it is being rotated, means' including a linkage for raising and lowering said restraining arm into and out of obstructing position from and to a nonobstructing position located below said path, said linkage having a lifting arm and a pivot arm operatively connected to said restraining arm at spaced points along the length thereof, said lifting arm having a permanently fixed pivot and said pivot arm having a movable pivot, and means for varying the position of said movable pivot so as to adjust the obstructing position of said restraining arm for cooperation with articles of difierent diameters.

4. In a machine for rotating a generally cylindrical article about its axis while said axis is in a substantially horizontal position of the type wherein the article is delivered to and from the rotating mechanism by movement along a substantially horizontal path, a safety device for preventing accidental ejectment of said article from the machine comprising a restraining arm having a portion adapted to be positioned above the upper surface of said article to obstruct bodily movement of said article while it is being rotated, means for raising and lowering said restraining arm into and out of obstructing position from and to a non-obstructing position located below said path, and means for controlling the relative speeds of raising and lowering movement of said restraining arm so that said arm may be lowered at a higher speed than that at which it is raised.

5. In a machine of the character described, the combination of means for rotating a generally cylindrical article about its axis while said axis is in a substantially horizontal position, rails on which said article is adapted to roll along a substantially horizontal path toward and away from opposite sides of said rotating means, said rails being positioned above the level of said rotating means, means for lowering and raising said article from and to the level of said rails to and from said rotating means, a hold-down arm adapted to prevent accidental ejectment of said article from said rotating means while said article is being rotated, and means for moving said hold-down arm into and out of an operative position, wherein the upper end of said arm is above said rails and adjacent to the upper surface of said article, from and to an inoperative position below the level of said rails, said arm moving means including a linkage connected to said hold-down arm having one arm rotatable about a permanently fixed pivot and operatively connected to the lower end of said hold-down arm and a second arm rotatable about a vertically adjustable pivot and operatively connected to said hold-down arm at a point intermediate its ends, means for applying actuating force to said linkage, and means for varying the position of said adjustable pivot so as to adjust the operative position of said hold-down arm to cooperate with articles of different diameters.

References Cited in the file of this patent UNITED STATES PATENTS 163,606 Peper May 25, 1875 522,093 Wolle June 26, 1894 1,783,094 Moore et a1 Nov. 25, 1930 1,944,168 Camerota Jan. 23, 1934 2,570,325 Dalton Oct. 9, 1951 2,671,260 Jessen et al. Mar. 9, 1954 2,751,617 McLaggan June 26, 1956 2,774,122 Hodler Dec. 18, 1956 FOREIGN PATENTS 345,502 Great Britain Mar. 26, 1931 637,206 Great Britain May 17, 1950

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