US2842160A

US2842160A - Charging apparatus for vinyl casting machines

Info

Publication number: US2842160A
Application number: US281337A
Authority: US
Inventors: Rekettye Paul
Original assignee: Sun Rubber Co
Current assignee: Sun Rubber Co
Priority date: 1952-04-09
Filing date: 1952-04-09
Publication date: 1958-07-08
Anticipated expiration: 1975-07-08

Description

July 8, 1958 P. REKETTYE CHARGING APPARATUS FOR VINYL CASTING MACHINES Filed April 9, 1952 6 Sheets-Sheet 1 FIG. 4

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CHARGING APPARATUS FOR VINYL CASTING MACHINES Filed April 9, 1 .952 I 6 Sheets-Sheet 2 INVENTOR. PAUL REKETTYE ATTORNEYS July 8, 1958 P. REKETTYE CHARGING APPARATUS FOR VINYL CASTING MACHINES Filed April 9, 1952 6 Sheets-Sheet 3 INVENTOR PAUL REKETTYE 6% ATTORNEYS July '8, 1958 P. REKETTYE 2,342,160

CHARGING APPARATUS FOR VINYL CASTING MACHINES Filed April 9, 1952 6 Sheets-Sheet 4 INVENTOR. PAU L REKETTYE ATTORNEYS July 8, 1958 P. REKETTYE CHARGING APPARATUS FOR VINYL CASTING MACHINES Filed April 9. 1952 6 Sheets-Sheet 5 INVENTOR.

PAUL REKETTYE BY v 9%, 1

ATTORNEYS 1 y 1958 P. REKETTYE CHARGING APPARATUS FOR VINYL CASTING MACHINES Filed April 9, 1952 6 Sheets-Sheet 6 INVENTOR.

PAUL REKETTYE ATTORNEYS CHARGKNG APFARATUS FOR VINYL CASTING MACHINES Paul Rekettye, Akron, Ohio, assignor to The Sun Rubber Company, Barberton, Ohio, a corporation of Ohio Application April 9, 1952, Serial No. 281,337

8 Claims. (Cl. ISL-565) In prior application Serial No. 179,726, filed August 16, 1950, now Patent No. 2,629,131, February 24, 1953, there is disclosed a machine for casting hollow articles such as dolls, toys, and the like in separable molds which are given a compound rotation while moved on an endless conveyor. The machine shown in that patent is the joint invention of the present applicant and Henry Martin.

In the manufacture of the articles described, the material used is a plastisol, usually a vinyl resin with a plasticizing agent, which is distributed over the inner surface of the molds or matrices and is gelled and fused by conducting the matrices through a heated chamber while the matrices are rotated simultaneously upon two axes. The matrices are subsequently opened for the removal of the finished articles and, While the matrices are open, they are conducted past a charging station where a nozzle is projected between the sections of the open matrix to deliver a measured charge of the casting material to each matrix. Thereupon, the nozzle is withdrawn, the molds are closed and locked, and the cycle is repeated.

The plastisol, when it is delivered to the mold, is quite viscous and stringy, and tends to cling to the mouth of the nozzle and drip over the machine. in the prior patent there was associated with the nozzle a drip cup adapted to follow the nozzle to the point where it passed between the matrix sections and then to return with the nozzle to its original position outside of the path of the molds to intercept any drip. While this "expedient kept most of the drippings from falling on the machine, it was not entirely satisfactory and there was considerable loss of the plastisol.

The object of the present invention is to design and perfect a form of charging nozzle by the operation of which there are no drippings from the charging nozzle, any drops which collect at the discharge point of the nozzle being drawn back into the nozzle.

The perfection of a nozzle to discharge measured quantities of the casting material without drip is complicated by the physical characteristics of the material itself, it being impossible to discharge this material without dripping by any known form of discharge nozzle.

The invention also includes the'combination with certain parts of the conveyor mechanism so that when the nozzle is projected between the open matrix sections, as they pass the discharge point, mechanism is operated for delivering a measured charge as required to form a complete article of the proper thickness.

In addition, the invention includes means for causing the nozzle to travel with each matrix for a sutficient distance to allow the complete charge to be delivered to the matrix. This improvement is of particular value when larger articles are being cast which require a quantity of the material in excess of what could be discharged in the time that the matrix is passing one point in the travel of the conveyor.

The invention as shown and described here is the nited States atent ice perfected form of the device, but the invention is not to be considered as limited to the specific design as it is capable of embodiment in other forms and modifications. The invention is shown as it is associated with the particular type of conveying mechanism of the above identified patent, but it may be used with other forms of conveyors. The invention, in certain aspects, may also be used to charge matrices while they are stationary.

While the invention has been particularly designed for the discharge of measured 'quantities of vinyl plastic, which is very difficult to handle due to the characteristics of the material itself, it may be used for the controlled discharge of a large variety of materials where it is desirable to have a discharge device which does not drip.

In the drawings, in which the preferred form of the invention is disclosed:

Fig. 1 is an exploded view showing the several parts of the nozzle in perspective.

Fig. 2 is a cross section of the nozzle in closed position on the line 22 of Fig. 8.

Fig. 3 is a cross sectional view of the nozzle in the discharging position where the casting material isflowing out of the nozzle into a matrix or other receptacle.

Fig. 4 is a similar view showing the nozzle after the measured charge has been delivered and the manner in which drops of the casting material are drawn back into the nozzle.

Fig. 5 is a side view of that portion of the conveyor system at and in the immediate vicinity of the discharge device. The conveyor system is, as explained, that which is shown and covered in the above mentioned prior .patent.

Fig. 6 is a view looking down on the charging mechanism, the location of the view being shown by the line 66 of Fig. 5.

Fig. 7 is a vertical section on the line 7-7 of Fig. 6.

Fig. 8 is a side view ofthe mechanism for projecting the nozzle between the matrix sections, the location of this View being indicated by the line 8-8 of Fig. 6.

Fig. 9 is a section on the line 9-9 of Fig. 6.

Figs. 10 and 11 are sections on the lines 10- -10 and 11-11, respectively, of Fig. 6.

Fig. 12 is a modified form of nozzle such as is used in a case Where there is a gang of matrices on a single matrix holder or when the cavity may be of such intricate design as to require that the charge be delivered at more than one point.

The Matrices and conveyor Referring to so much of the-conveyor mechanism and matrices as is necessary for a complete understanding of the invention:

An endless conveyor chain is indicated by the numeral 1; This chain is continuously operated and is guided and propelled through the cycle required for casting and removal of the finished articles by a series of sprockets, two of which are shown at 2 and 3 as supported in a framework indicated as a whole at 4. During its travel, after the matrices are charged, closed and locked, the conveyor passes to means which rotates the matrices in a plurality of planes to distribute a charge over the inner wall of each matrix. The matrices are then carried through a heated chamber, where the vinyl resin is fused and set, and thence through a cooling zone. During the balance of the conveyor travel, after leaving the heated chamber, the matrices are not rotated. Each matrix passes a point where it is opened, and the conveyor then passes over the sprocket 2. The instrumentalities just discussed are not shown herein, reference being made to the aforesaid prior patent.

As the conveyor passes upwardly in its vertical flight between sprockets 2 and 3, the operator removes the finished articles and then the matrices pass to the loading point.

Matrices are shown in the drawing at 5, each consisting of a lower section 5a, which is stationary in the matrix holder, and an upper section 5b, which is moved to open and close the matrix. A matrix holder is shown at 6 and consists of a yoke, to one arm of which the section 5a is fixed by a stem or pin 7. The movable matrix section is carried on a bar 8 which is slidable in the other arm of the yoke to and from the stationary section. The outer end of each bar 8 is provided with a roller 16 which, when the matrix is closed, rests in a seat 11 on the end of the yoke. A movable latch 12 engages a notch in the bar 8 to lock the two matrix sections together and means are provided to operate the latch to lock the matrix sections together after the charge is delivered, and to unlock the matrices after the operation is complete to permit the matrices to open as shown in Fig. 5, all of which is fully set forth in the aforesaid patent.

Each yoke 6 is carried on a crank arm 18 which is carried by one of the links of the chain conveyor and is rotated by appropriate mechanism during that portion of the conveyor travel not shown in the drawings. At the same time, the yokes are rotated on their own axes through the rotation of a shaft 19, which is driven by a chain 20 during the movement of the conveyor, which rotation is transmitted to the yoke through the bevel gearing 22. This gives the compound rotation.

However, during the period with which we are dealing here, the yoke and the matrix are not rotating; the movable upper section 5b is held in raised position and guided by the engagement of the rollers with the upper surfaces of spaced guide rails 25, which are supported upon side plates 26 and receive between them the bars 8. As shown in Fig. 5, the yokes are turned as they pass around the sprocket 3 so that the section 5b of each matrix is raised above the lower matrix section and held in that position until the measured charge is delivered to the lower section. After the charge is delivered, the rollers 10 pass 01f the ends of rails 25 and the upper matrix sections drop onto their respective lower matrix sections and are driven into tight engagement by the hammers 26 which descend as each matrix passes beneath it. At the same time, the latch 12 is engaged and the matrix locked.

In Fig. 5, the matrix which is receiving the charge is located just to the right of the hammer.

The charging mechanism The charging mechanism is located on a shelf or platform 30 supported on the framework of the machine. The nozzle as a whole is indicated by the numeral 32 and is secured to the end of a supporting arm or rod 33, the inner end of which is provided with a collar 34, swiveled on a pin 35 to which it is held by a nut 36. Pin 35 rises from a head 38 having a long stern 39which is guided in a collar 40 secured to the shelf 30. The head 38 is attached by pin 42 to the end of a piston rod 43, which is actuated to and fro by fluid pressure in the cylinder 44 carried by the platform 30.

The mechanism just described projects the charging nozzle between the two sections of each matrix as it passes the charging point, as shown in dotted lines in Fig. 6, and after delivering the charge the pressure in the cylinder is reversed, returning the nozzle to the idle position shown in full lines. The operation of the valves to project and retract the charging arm is controlled by the matrix itself, as will be explained.

The arm which carries the charging nozzle may have the forward and return stroke only, but in the casting of larger hollow articles a somewhat longer period may be required to deliver a full charge and it is for this reason that the arm 33 is pivoted on the head 38. The arm 33 is yieldingly held against a roller 46 mounted in a fork 47 attached to a bracket 48 rising from the platform, so

that it may move away from the roller with the conveyor for a sufiicient interval to allow the nozzle to follow a matrix and discharge its full load into the moving matrix. This is shown by the dot and dash line in Fig. 6. A coil spring 50, one end of which is attached to a pin 51 extending from the arm 33 and to the bracket 48 returns the arm to its normal position resting against the roller 46 after the charge is delivered.

The rocking movement is imparted to the nozzle assembly by means of a light wire loop 55, which is attached to the arm 33 and is in position to lie in the path of each yoke 6 as the nozzle comes in register with the lower matrix section. The progression of the yoke thus carries the nozzle assembly forward until the yoke clears the loop 55, which will usually occur just as the nozzle is returned by the removal of the piston in cylinder 44.

When the discharge nozzle is over a matrix, the mechanism to deliver the measured charge is operated and will continue to function until the whole charge is delivered, which will be just before the charging nozzle is withdrawn.

The measured charge is delivered to a chamber 58 formed in the top of the nozzle 32 through a flexible hose 59 coupled on the nozzle. The other end of the hose is connected to a chamber 60 formed in a housing 61 attached to the platform 30. The casting material is delivered to the chamber 60 through a conduit 62 which is connected to a fitting 64 having a restricted delivery orifice 65. Seated at the orifice is a ball valve 66 yieldingly held against the orifice by a spring 67, the lower end of which rests upon a plug 68 threaded into a stirrup 69 depending from the fitting. The ball valve opens to admit the casting material to the chamber 60 when the pump, to be described, is on its return stroke and closes on the forward stroke of the pump so that the charge will be forced through the hose 59 to the nozzle.

The pump 72 comprises a cylinder in which is located the piston 74, the rod 75 of which extends to the rear of the pump where it is threaded to receive an adjustable stop collar 76 which strikes the bushing 77 on the feed stroke of the pump and arrests the forward movement. Preferably, the rod 75 is graduated so as to enable the operator to set the pump to deliver the exact amount of the charge for each matrix. The rear end of rod 75 is threaded to a piston rod 79 operable by the double acting cylinder 80.

There are four movements of the charging mechanism, all of which are imparted to the mechanism by the operation of the

cylinders

44 and 80, both of which are reversible and controlled by suitable valve mechanism actuated by solenoids (not shown). The solenoids are energized by micro-switches located in the path of the matrix holders. Conveniently, these micro-switches are mounted between the side plates 26 and are in position to be struck and operated by the roller 10. The first switch, indicated at 82 in Fig. 5, operates the valve in the cylinder 44 to project the nozzle between the matrix sections. The second switch 83 operates the valve to the cylinder to project the pump forwardly to deliver the measured amount to the nozzle as determined by the setting of the collar 76. The third switch 84 reverses the valve to cylinder 80 and returns the pump to its former position, it being noted that this movement creates a vacuum at the nozzle due to the withdrawal of the piston 72. The fourth switch 85 acts on the valve of cylinder 44 to retract the entire nozzle assembly.

By the means which has been described heretofore, the nozzle is automatically projected between each pair of matrix sections as it reaches the delivery point. The nozzle travels with the moving matrix section for some distance to allow for the complete discharge. As the nozzle reaches the position between the matrix sections, the pump delivers the charge to the nozzle and then returns. The nozzle assembly is now withdrawn.

Drip prevention is provided by the construction of the nozzle, which has been given the general reference numeral 32 and is shown in detail in Figs. 1 to 4, inclusive.

At the chamber 58 previously referred to, the delivery .passage for the plastisol is given a right angular turn and is threaded to receive the main body portion of the nozzle which is given the reference numeral 90. Intermediate of the bodyis the collar 91 which bears against the lower end of the chamber part 58 and at its lower end the portion 90 is reduced and tapered, as at 92, terminating in a sharp edge portion surrounding the discharge outlet. In the upper part of body 90 is force fitted a collar 95 having a ring of ports 96 which permit the passage of the casting material from the chamber 58 to a smaller chamber 98 in the body 90. Centrally located in the collar 95 is a passage 99 in which is slidably mounted the hollow stem 100 of what may be termed a supplemental or auxiliary nozzle 101. The lower part or body of the supplemental nozzle is enlarged and hollow, as shown, and its lower edge is brought to .a sharpened knife-like rim 102 which, when the nozzle is closed, rests upon and exactly matches the sharp edge 93 on the main nozzle body. The lower edge of the supplemental nozzle forms a sealing ring which closes the narrow crack between the main nozzle 92 and the valve 110. At either side of the nozzle 101 are passages 104 which permit the casting material to flow into the third chamber 105 in the supplemental nozzle. A coil spring 106 surrounding the stem 100 between the collar 95 and the head of the supplemental nozzle yieldingly holds the two nozzles in nested position, as shown in Fig. 2, with the

sharp edges

93 and 102 in coincidence.

Slidably mounted in the stem 100 is the upwardly extending stem 108 of the valve proper 110. This latter is the cone-shaped body depicted in the views having a sharp edge portion 111, which, when the valve is closed, coincides with the

sharp edges

93 and 102 so that all three form substantially one line about the discharge port of the nozzle. The body of the valve, when it is moved downwardly as shown in Fig. 3, opens the discharge port and admits the passage of a measured charge of the plastisol as determined by the forward stroke of the pump. A coil spring 114 surrounding the upper end of the stem 108, where it projects into the chamber 58, and held between a nut 115 threaded on the top of the stem and the stem 100 will normally keep the valve elevated and closed, but will yield due to the pressure exerted upon the plastisol in the nozzle by the forward stroke of the pump to open the valve and discharge the liquid.

While there may be a few drops which cling to the surface 102 of the supplementary nozzle, as the plastisol flows around the valve proper 110, it will cling to the edge 1111, sometimes to the extent of forming a complete depending skirt around the valve which will string out in long drops which would eventually drip. This condition is attempted to be shown in Fig. 3.

The return stroke of the pump 72 creates a suction through the body of the plastisol in the pipe 59 and the nozzle and this suction acts on the valve 110 to draw it back into the nozzle body, carrying the supplemental nozzle with it. The valve holds back any plastisol but the inward movement of the valve brings any drops clinging to the valve 110 into the interior of the nozzle, as shown in Fig. 4, where the suction exerted by the pump draws the drops into the main body of the plastisol, as shown in Fig. 4. Any drops clinging to the part 102 are likewise returned to the main body.

At the end of the return stroke, the pressure on the plastisol is returned to normal or balanced pressure and the valve closes to the position shown in Pig. 2.

The form of the invention shown in Fig. 12 is adapted for the charging of multiple cavity matrices or large or intricate matrices, where it may be desirable to distribute i 6 the charge over a greater area. In'this case, the pivoted delivery arm is given the numeral 120. The arm is hollow and receives the charge of casting material through the-conduit 121 and delivers it to a manifold 122, which,

through openings 123, transfers the charge to two smaller cross heads 124, from each of which extend two nozzles 125 similar in construction and operation to the nozzle 32 heretofore described. A wire 126 similar to the wire 55 causes the arm to move with each matrix as it passes the charging point.

It will be seen that a novel and ingenious mechanism has been devised for preventing any drippings of the charging material from the nozzle. The provision of means by which the valve is returned to a position within the nozzle after delivering its charge, in combination with the supplemental nozzle which holds back the main body of the material while the drops are being returned, is a novel and ingenious solution of the problem of preventing dripping of these materials which are so viscous and stringy as to require some special handling.

While the invention shown and described herein has particular utility in conjunction with the casting material of the prior application, it may be used wherever material having physical characteristics similar to the plastisol handled in this application is to be discharged without objectionable dripping. Preferably the device is used in combination with the means for delivering measured amounts at frequent intervals.

What is claimed is:

1. A device for delivering charges of a viscous liquid such as a plastisol, without dripping, said device having a chamber, a pump intermittently operated for feeding liquid to the chamber and exerting alternate pressure and vacuum on the liquid in the chamber, the chamber having an outlet, a valve at the outlet, a mounting for the valve permitting it to project beyond the outlet by the pressure exerted on the fluid by the pump or be withdrawn into the outlet by the suction exerted on the fluid by the pump.

2. A device for delivering charges of a viscous liquid such as a plastisol, without dripping, said device having a chamber, a nozzle in the chamber having a discharge opening, a valve in the nozzle, a mounting for the valve having yielding means to hold the valve in the opening but to permit it to project beyond the nozzle or to move to a position withinthe nozzle, and means to exert pressure or suction on the liquid alternately, first to project the valve beyond the nozzle and open the nozzle for the intermittent discharge of measured amounts of the liquid and then to withdraw the valve inwardly of the opening.

3. In a device for delivering a measured charge of a viscous liquid without dripping, a nozzle having'a discharge opening, a pump for forcing a predetermined amount of liquid to the nozzle, said pump being reversible to create suction on the liquid in the nozzle after delivery of the charge, a valve in the nozzle, said valve closing the discharge opening when the pump is idle, and a mounting for the valve by which it is movable outwardly of the nozzle on the delivery stroke of the pump but is movable to a position within the nozzle on the reverse operation of the pump.

4. A device for delivering a charge of viscous liquid, comprising a nozzle having a discharge opening, a valve having an external diameter not greater than the diameterof the opening, means to hold the valve in position to close the opening when the pressure on the liquid in the nozzle is balanced, but which allows the valve to move beyond the opening when the liquid in the nozzle is moving toward the opening, and allows the valve to move to a position within the nozzle when the liquid in the nozzle is moving inwardly from the opening, and means operating alternately to feed the liquid in measured amounts under pressure to the nozzle and to exert suction on the liquid at the nozzle.

5. A device for delivering a charge of a viscous liquid without dripping, comprising, a conduit communicating with a pump and a source of said liquid, a hollow nozzle attached to the outer end of said conduit, the walls of the outer end of said nozzle converging to define a sharpedged circular opening, a valve stem positioned concentrically of said nozzle, and a valve afiixed to the lower end of said stem, said valve being conical and having a sharp-edged lower periphery slidably interfitting within the circular opening of said nozzle.

6. A device for delivering a charge of a viscous liquid without dripping, comprising, a conduit communicating with a pump and a source of said liquid, a hollow nozzle attached to the outer end of said conduit, the walls of the outer end of said nozzle converging to define a sharpedged circular opening, a yielding valve stem mounting located interiorly of said nozzle above said opening, said mounting having a series of liquid passages therethrough, a valve stem movably supported by said mounting concentrically of said nozzle, and a valve afiixed to the lower end of said stem, said valve being conical and having a sharp-edged lower periphery slidably interfitting within the circular opening of said nozzle, said valve being capable of extension through said annular opening when pressure is applied by said pump to said liquid.

7. A device for delivering a charge of a viscous liquid without dripping, comprising, a conduit communicating with a pump and a source of said liquid, a hollow nozzle attached to the outer end of said conduit, the walls of the outer end of said nozzle converging to define a sharpedged circular opening, a valve stem positioned concentrically of said nozzle, a valve affixed to the lower end of said stern, said valve being conical and having an undercut lower face defining a sharp edge with a diameter slidably interfitting within the circular opening of said nozzle, and a supplementary nozzle movable upon said valve stem above'said valve, the wall of the outer end of said supplementary nozzle sharply converging to define a ring of substantially the same diameter as that of said circular opening.

8. A device for delivering a charge of a viscous liquid without dripping, comprising, a conduit communicating with a pump and a source of said liquid, a hollow nozzle attached to the outer end of said conduit, the walls of the outer end of said nozzle converging to define a sharpedged circular opening, a yielding valve stem mounting located interiorly of said nozzle above said opening, said mounting having a series of liquid passages therethrough, a valve stem movably supported by said mounting concentrically of said nozzle, a valve affixed to the lower end of said stem, said valve being conical and having an undercut lower face defining a sharp edge with a diameter slidably interfitting within the circular opening of said nozzle, and a supplementary nozzle movable upon said valve stem above said valve, the wall of the outer end of said supplementary nozzle sharply converging to define a ring of substantially the same diameter as that of said 'circular opening.

References Cited in the file of this patent UNITED STATES PATENTS 1,087,890 Rogers Feb. 17, 1914 1,140,259 Elliott et al. May 18, 1915 1,213,710 Timpson Jan. 23, 1917 1,229,885 Chadwick June 12, 1917 1,843,701 Stokes Feb. 2, 1932 2,017,686 DeValera Oct. 15, 1935 2,210,971 Bronson Aug. 13, 1940 2,300,273 Connell Oct. 27, 1942 2,661,761 Samiran Dec. 8, 1953