US2760653A

US2760653A - Pneumatic apparatus for controlling the flow of sand from a sand hopper

Info

Publication number: US2760653A
Application number: US321682A
Authority: US
Inventors: Harry C May
Original assignee: Westinghouse Air Brake Co
Current assignee: Westinghouse Air Brake Co
Priority date: 1952-11-20
Filing date: 1952-11-20
Publication date: 1956-08-28
Anticipated expiration: 1973-08-28

Description

H. c. MAY 2,760,653 PNEUMATIC APPARATUS FOR coNTRoLLING THE mow oF SAND FROM A SAND HOPPER Filed Nov. 2o, 1952 Unite tts PNEUMATIC APPARATUS FOR CGNTROLLING THE FLOW F SAND FRM A SAND HPPER Harry C. May, East McKeesport, Pa., assigner to Westinghouse Air Brake Company, Wilmerding, Pa., a corporation of Pennsylvania r[his invention relates to control apparatus and more particularly to the iiuid pressure type for controlling a plurality of diierent operations such as those relating to the control of supplying sand to a molding machine.

One method of supplying sand to a molding machine is by means of a conveyor belt carrying sand above the machine, the sand being diverted from the conveyor belt to a hopper by means of a mechanical plow. From the hopper the sand falls by gravi-ty into a basket from which rthe operator of the molding machine draws the sand for his work. The amount of sand in the basket is controlled by a scale beam which supports the basket and controls the plow in such a manner that when the amount of sand in the basket drops to a certain limit in weight, the scale beam causes the plow to divert more sand from the belt to replenish rthat in the basket, and when thus increased to a certain greater limit, the scale beam causes the operat-ion of the plow to be stopped, it being intended that this operation of `the apparatus maintain an adequate amount of sand available in lthe basket at all times for molding operations. The sand, however, has an occasional tendency to build up in the hopper rather than flow freely to the basket. When this occurs, while the basket is waiting for more sand, the plow may continue diverting sand from the conveyor belt into the hopper, until said hopper overiows. This may result in undesired and costly delay until the situation is corrected and the molding machine can be put into operation again.

One object of the invention, therefore, is to provide a uid pressure control apparatus which is automatically operative to insure the maintaining of an adequate amount of `sand in the basket available to the molding machine operator at all times.

Another object of the invention is ythe provision of means for preventing build-up of sand in the hopper of a sand supply control iapparatus so that the ow of sand from said hopper into the basket will go on unobstructed.

Another object of the invention is the provision of an improved sand supply control apparatus for a molding machine which is so constructed and arranged as to eliminate delay in time, and, hence, unnecessary cost in a molding operation due to a possible failure, such as above described.

In the accompanying drawing, the single gure is an elevational View, partly in outline and partly in section, of a control apparatus embodying the invention.

Description As shown in the drawing, the apparatus, embodying the invention, comprises a movable conveyor belt 1 adapted to carry molding `sand over the top open end of a hopper 2, a plow 3 being provided for vertical movement into the path of movement of the sand on the belt 1 for diverting sand therefrom into the top of said hopper. Sand thus diverted into the hopper 2 is adapted to flow by gravity through a lower open end 2a of said hopper into a vertically movable basket 4 from which an operator may draw "atet rg n ICE

sand for molding purposes, said basket being carried by `one end of a scale beam mechanism 5 which at its center is fulcrumed on a pin 78 carried by a iixed bracket 6.

The hopper 2 and the plow 3 are carried by a fixed rigid bracket 7 which also carries a plow operating fluid motor 8 for moving the plow 3 vertically into and out of the path of movement of the sand on lthe belt 1. The motor 8 is arranged for control by a relay valve `device 9 which is in turn controlled by a pilot valve device 10 fixed with respect to the hopper 2 and controlled by basket 4 through the medium of a stop device 11 xed to and movable with said basket. The apparatus further comprises a pneumatic hopper vibrator device 12 associated with a sloping side 2b of the hopper 2 and arranged for control by the relay valve device 9, and a suitable source of iiuid under pressure such as in reservoir 13.

The mechanical plow 3 comprises a blade 14 disposed perpendicularly and generally transversely -to the plane of the conveyor belt 1. The blade 14 is rigidly mounted on a lever 15 at one side of a horizontally arranged fulcrum pin 16 carrying said lever and in turn carried by the bracket '7, While at the opposite side of said pin said lever is connected by a pin 17 to a depending link 18.

The plow operating motor 8, disposed Ibelow the link 18 comprises a casing 19 and a piston 2t) mounted therein for vertical movement and cooperative with said casing yto form at one side of said piston a pressure chamber 21 connected through a pipe Sii to a chamber 45 in the relay valve device 9. At the opposite side of the piston 20 there is a non-pressure chamber 22 open to atmosphere by way of a port 23. The pis-ton 20 is provided with a suitable seal (not shown) Ito prevent leakage of iluid under pressure from pressure chamber 21 to non-pressure chamber 22 and is also provided with a vertically and coaxially arranged piston rod 24 attached at its lower end to the piston 20. The rod 24 extends through a top wall 25 of the vcasing 19 and has its opposite end connected to the link 18 and thereby to the respective end of the plow lever 15 by means of the pin 17. A return spring 26 contained in chamber 22 and encircling piston stem 24 acts on piston 26 urging same toward a normal position or what may be called a sand supply cut-oli position 'adapted to be dened by engagement of link 18 with a stop collar 27 formed integral with the casing 19. in this cut-olf position of piston 2li the plow blade 14 will be in a position, indicated by dash and dot lines in the drawing, out

of the path of movement of sand on belt 1. The plow blade 14 also has a plowing position, in substantial contact with belt 1 for `diverting sand therefrom int-o hopper 2 and will be moved thereto by piston 20 against spring 26, as will be later described. In the drawing the plow blade 14, lever 15 and piston 20 are shown, in full-lines, in this position for diverting sand to hopper 2. The lower end of the motor casing 19 is rockably supported on a pin 28 carried by a bracket 29 secured to the bracket 7. The relay valve device 9 comprises a casing 31 having lsecured between two sections thereof a flexible diaphragm 32 at one side of which there is a pressure chamber 33 and at the opposite side a chamber 34 which is open to 'atmosphere through a port 35. In chamber 34 the diaphragm 32 engages a diaphragm follower 36 provided on one end of a stem 37 which extends through a partiy formed in casing wall 38, encircles and has sealing and sliding contact with the peripheral surface of `the diaphragm follower stem 37 to prevent leakage of 4fluid under pressure from chamber 39 past said, diaphragm follower stem into chamber 34 which, as previously noted, is

Patented Aug. 28, 1956 opent to atmospherethrough port 35. In chamber 39 the end of stern 37 engages a poppet valve 42 which has a lluted stem 43 slidably guided in a bore extending through a partition wall 44 separatingchamber 3g from chamber 45, a seat being provided for said valve around `the end of said bore which opens to chamber 39. An oppositely and coaxially arranged poppet valve 46 contained in a chamber 47, separated from chamber by a partition wall 48, has a-iluted stem 49 extending through a bore in said Wall into chamber 45 wherein it engages the end of valve stern 43; a sea-t for said valve being provided mound the end of said 4bore opening to chamber 47. The abutting valve stems 43 and 49 are of such length that when either

valve

42 or 46 is seated, the other will be unseated. A bias spring 50 in chamber 47 acts on valve 46 urging it toward a normal seated position and valve 42 toward a normal unseated position.

In the relay valve device, 9 diaphragm` chamber 33 is connected through a pipe 51 to the pilot valve device 1i?, chamber 45 is connected by pipe 3i) to pressure chamber 21.in the operating motor 8, chamber 47 is connected via apipe 52 to the lluid pressure supply reservoir 13, and

chamber 39 is connected to the vibrator device 12 via a pipe S3.

The hopper vibrating device 12 may be of any suitable type, but preferably is a pneumatic type, such as that disclosed in the patent to Harris Tabor, No. 533,401, issued January 29, 1895, and therefore adapted to be operated by uid under pressure to create a vibration of the hopper walls, the pipe 53 constituting a liu-id pressure supply pipe for said device.

The pilot valve device 10 comprises a casing 54 having chambers 57 and 5S wherein are contained two oppositely seating and coaxially arranged

poppet valves

55 and 56 having oppositely arranged lluted

stems

59 and 60, respectively.

Sterns

59 and 60 extend through bores in partition walls 61 and 62, respectively, into an intermediate chamber 63 wherein said stems abut one another and which is separated from chambers 57 and 58 by said walls, a seat being provided on said walls for the respective valves. A bias spring 64 in chamber 57 acts on valve 5S urging said valve toward a normal seated position and valve 56 toward a normal unseated position. A port 65 in the casing 54 connects chamber 58 to atmosphere. Chamber 57 is connected to supply reservoir 13 via pipe 52, and hence adapted in use `to be constantly supplied with lluid under pressure. In chamber 58 valve 56 isengaged by one end of a stem 66 projecting downwardly, as viewed in the drawing, through a bore in the casing 54 into contact with a vertically rockable lever 67, intermediate its ends, which lever is rockably mounted at one end on a horizontally arranged pin 68 supported by the casing 54 and provided at the opposite end with a pin 69 carrying a roller 70. Rocking motion of the lever 67 in anupward direction is adapted to be limited by the stem66 upon seating of valve 56 and in the opposite direction by engagement of lsaid lever with a stop 71 associated with the casing 54.

The roller of the pilot valve device 10 is adapted to contact a head 72 provided on one end of a vertically movable plunger 73 in the stop device 11, said plunger being` slidably mounted in a bore through a bracket 74 which is mounted on an -outer surface of the basket 4 near its top. AY spring 75, under compression and encirclingl che plunger 73, is supported at one end on the bracket 74 with its other end bearing against the plunger head 72 urging same against the roller 70. At the opposite side yoli the bracket 74 a stop nut 76 is secured to the plunger 73V to engage bracket 74 and thereby limi-t upward movement of said plunger by the spring 75.

The scale beam mechanism` 5 comprises a scale beam 77 rockably mounted intermediate its ends onV the fulcrum pin 78 carried by the bracket 6. One endof the beam 77 is supportingly connected to the vertically movable basket 4 by means of a pivot pin 79 associated with said basket. At the opposite side of fulcrum pin a counter-balancing weight 80 is freely slidable onthescala beam 77 in a groove 81 between an innermost position in contact with bracket 6 and an outermost position which may be delined by a stop 82 associated with said scale beam. Associated with the bracket 6 is a stop 83 adapted to limit downward motion of the basket 4 by engagement of the scalebeam 77 with said stop.

Operation inA operation, assuming that the reservoir13 is` charged with fluid under, pressure, the pressure chambersV 57v and 47 in the pilot valve device 10 and the relay valve device 9, respectively, will also be charged with lluidunder pressure via pipe 52. Also let it be assumed that the conveyor belt l be loaded with sand and traveling across lthe top of hopper 2.

Still further let it be assumed that, due to use, the weight of sand in the basket 4 has been so reduced that :thescale beam weight 89 has rocked said scale beam in acounter.- clockwise direction, as viewed in the drawing, andraised said basket vertically to a loading position in whichit is shown in the drawing. With the basket 4 thus positioned, lthe angularity of the scale beam 77 to the horizontal Will also be substantially as shown in the drawing. With the, scale beam 77 thus positioned, the counterweight 80, due to gravity, will have slid along the groove 81 insaid beam to its outermost position in contact with the stop 82.

With the scale beam 77 and the basket 4 positioned-,as shown in the drawing, the plunger head 72 of the stop device 11 will be in contact with roller 70, causing said roller to position lever 67 to seat valve 56 and unseat valve 5S in the pilot valve device 10, the Ispring 75 in the stop device 11 being compressed solid as necessary to unseat valve S5 against spring 64 in said device.

With valve 56 in the pilot valve device 10 seated, chamf ber 63 therein is disconnected from atmosphere via cham-v ber 5S, while the unseating of valve 55 permits lluid under pressure to flow from reesrvoir 13 to diaphragm chamber 33 in the relay valve device 9. When` sucient, pressure is thus obtained in chamber 33 to overcomeY opposing pressure of spring 4t), of spring Sll and of iluid in chamber 47 acting on valve 46, said diaphragm will deflect out of a normal position` against spring 40, and through stern` 37 seat valve 42 and unseat valve 46. The seating of valve 42 closes chamberV 45 from, chamber 39 while unseating of valve 46 opens chamber 45 to chamber 47 whereupon iluid under pressure will ow from the.

reservoir 13 through pipe 52 to pipe 30 and thence to chamber 21 in the operating motor 8.

When the pressure of fluid thus provided, in chamber 21 and acting on piston 20 of the operating motor 8 is increased sufficiently to overcome the opposingforce of spring 26, said piston will move vertically upward out of a normal position and rotate the lever 15 about pin 16 in a counter-clockwise direction, as viewed in the drawing, and move the sand plow blade 14 into the sand yon the conveyor belt 1 to divert sand from said belt into the hopper 2 from whence it will fall by gravity into the basket 4.

This transfer of sand from the conveyor belt 1 through. the hopper 2 and into the basket 4 will continue until said basket has been filled with sand suiciently to overv balance the counterweight 80, which at this time is in its outermost position, in which it is shown in the drawing. When this condition is obtained, the weight of the basket 4 and the sand therein will start to rotate the scale beam 77 in a clockwise direction about the pin 78 causingsaid basket to move vertically downward. When` a suicient load of sand is thus obtained in the basket 4; to turn the scale beam 77 clockwise past a horizontal position thereof,vthe weight S0, due to gravity, will slide along groove 81 toward its innermost position, thereby increasing the mechanical advantages of the scale beam mechanism in favor of the basket and load carried thereby which will provide prompt and positive movement of the basket to the position defined by contact of the scale beam 77 with the stop 83. During this movement of the basket 4, and consequently of the stop device 11, spring 64 will seat valve 5S and unseat valve 56 in the pilot valve device 10, following which spring 75 will expand maintaining the plunger head 72 in engagement with the roller '70 until the stop nut 76 engages the bracket 74 after which the plunger 73 will move downwardly with the basket 4, the lever 67 moving with the plunger head 72 until it contacts the stop 71.

With the seating of valve 55 and the unseating of valve 56 in the pilot valve device 1d, the supply of iiuid underpressure is cut off to chamber 33 in the relay valve device 9, and the uid under pressure in said chamber is permitted to escape to atmosphere through pipe 5i, chamber 63, past the fluted valve stem 60 into chamber 58 and thence through port 65. Having thus vented the fluid under pressure in chamber 33 to atmosphere, the bias spring it? will move the diaphragm 32 and the follower 37 vertically upward to normal position, and bias spring 50 will seat valve 46 and unseat valve 42 in the relay valve device 9.

The seating of valve 46 in the relay valve device 9 will cut o further supply of fluid under pressure to the pressure chamber 2l in the operating motor S while the unseating of valve 42 will permit release of fluid under pressure from said motor through the vibrator device 12 via pipe 53. Upon release of uid under pressure from the motor chamber 21 the return spring 26 will move piston 2i) and thereby the piston rod 24 vertically downward to their normal positions. This movement of the piston 2i) and the piston rod 24 will rock the lever 15 to pull the plow blade i4 out of the sand on the conveyor belt l so that plowing operation will cease.

The fluid under pressure released from the motor chamber 2l to the vibrator device l2 will cause operation thereof to vibrate the sloping side 2b of the hopper 2, thus shaking into the basket i any sand which might have stuck and backed up on said sloping side.

With the basket l in its lower position, defined by contact of scale beam 77 with stop S3, and with the weight 80 in its innermost position against bracket 6, the mechanical advantage of the scale beam mechanism 5 with respect to said weight will be at a minimum thus permitting the molder to use substantially all the sand in said basket for molding purposes without change in position of said bracket.

When, due to use, a molder has reduced the amount of sand in basket 4 to an extent where the weight of said basket and the sand remaining therein is less than the counterbalancing eect of weight Si), the latter weight will overbalance the weight of said basket and remaining sand and rotate the scale beam 77 in a counter-clockwise direction, as viewed in the drawing. When the scale beam 77 has thus rotated past the horizontal, the weight 80, due to gravity, will slide along groove 81 to its outermost position in contact with stop 82 so as to permit the scale beam mechanism 5 to provide a maximum mechanical advantage with respect to said Weight which will cause prompt movement of basket 4 to its loading position, in which it is shown in the drawing, and which will also permit the basket 4 to be substantially lled with sand, as hereinbefore described, before the weight of said basket and the sand therein will overbalance the weight 39 on the scale beam 77.

When the basket approaches the loading position, in which it is shown in the drawing, the stop device 11 engages roller 70 without severe shock, due to the cushioning effect of spring 75, and then actuates said roller to rock lever 67 in the pilot valve device 10 in a clockwise direction to seat valve 56 and unseat valve 55 in said device for thereby initiating another cycle of operation of the apparatus to load the basket 4 with sand followed by cut off of the sand supply to said basket and operation of the vibrator device 12 to clear the sloping wall 2b of the hopper of stuck sand, the same as hereinbefore described.

Summary From the foregoing it will be seen that I have provided a fluid pressure control apparatus which is automatically operative for assuring timely delivery of sand, as needed, through the sand-supplying equipment for a molding machine, said apparatus embodying means which prevents failure of the sand supply due to back up in the hopper by eliminating such back up which in turn avoids pos sibility of sand overflowing the hopper with undesired and costly delay in molding operations.

Having now described my invention, what l claim as new and desire to secure by Letters Patent, is:

l. A control apparatus comprising, in combination, a source of uid under pressure, a fluid pressure operable motor device, a fluid pressure operable vibrator device, relay valve means operable in one position to connect said source to said motor device and having a normal position in which fluid under pressure from said motor device is connected to said vibrator device, pilot valve means having a rst position for connecting said source to said relay valve means and having a normal position for establishing communication between said relay valve means and atmosphere, a scale beam fulcrumed intermediate its ends, a stop device engageable with said pilot Valve means to move said pilot valve means to said irst position, a vertically movable load carrying basket carried by one end of said beam and carrying said stop device, and a counter-weight on the other end of said beam for rocking said scale beam in a direction to lift said basket and actuate said stop device to move said pilot valve means to its said first position, the weight of said load and basket upon preponderance over said counter-Weight being operable to rock said beam in the opposite direction and move said stop device out of operating relation with said pilot valve means, said pilot valve means including means operable when said stop device is out of operating relation with said pilot valve means to move said pilot valve means to its normal position.

2. A control apparatus comprising, in combination, a source of liuid under pressure, a hopper for receiving sand, a conveyor belt arranged to carry sand over said hopper, a plow for diverting sand from said belt into said hopper, a motor device operable by fluid under pressure to move said plow into diverting relation with said sand and upon release of fluid under pressure to move said plow out of such relation, a fluid pressure operable vibrator device associated with said hopper for vibrating said hopper, valve means for selectively controlling the supply of uid under pressure to said motor device and the release of iiuid under pressure therefrom to said vibrator device, respectively, pilot valve means and a weighing mechanism for controlling said pilot valve means comprising a sand-receiving basket disposed beneath said hopper to receive sand diverted thereinto and operable in response to a chosen weight of sand therein to operate said pilot valve means for effecting operation of the iirst said valve means to cut off the supply of fluid under pressure to said motor device and release fluid under pressure therefrom to said vibrator device.

3. A control apparatus comprising, in combination, a source of iluid under pressure, a iluid pressure operable motor device, a fluid pressure operable vibrator device, relay valve means having a pressure chamber therein and operable in response to iluid under pressure therein to one position for connecting said source of iiuid under pressure to said motor device and operable upon release of fluid under pressure from said chamber to a normal position for disconnecting said source of uid under pres# sure from said motor device and for releasing fluid under pilot valve means having a tirst position for connecting supported said source of fluid under pressure to said chamber and a normal position for disconnecting said source of uid under pressure from said chamber and for venting said chamber to atmosphere, and mechanical means for selectively controlling said pilot valve means.

4. A control apparatus comprising, in combination, a source of fluid under pressure, a hopper for receiving sand, a conveyor belt arranged to carry sand over said hopper, a plow for diverting sand from said belt into said hopper, a motor device operable by fluid under pressure to move said plow into diverting relation with said sand and upon release of iluid under pressure therefrom to move said plow out of such relation, a liuid pressure operable vibrator device associated with said hopper for vibrating same, relay valve means having a iirst position for connecting said source of fluid under pressure to said motor device and a normal position for disconnecting said source of iluid under pressure from said motor device and for establishing a communication to convey tiuid under vpressure from said motor device to said vibrator device, pilot valve means operable to a rst position to establish a communication between said source of fin-id under pressure and said relay valve means and operable to a normal position to establish a communication between said relay valve means and atmosphere, and a weighing mechanism for controlling said pilot valve means comprising a scale beam fulcrumed at a point intermediate its ends, a vertically movable sand-receiving basket carried at one end of said beam and disposed beneath said hopper, a resilient stop device carried by said basket and adapted to engage said pilot valve means, and a counter-weight slidably mounted on said beam at the opposite side of its fulcrum for rocking said beam to lift said basket and consequently said stop device into engagement with said pilot valve means for actuating said pilot valve means to its tirst position, said beam being operable upon a preponderance of the weight of said load and said basket over said counterweight to rock said beam in the opposite direction and move said stop device out of contact with said pilot valve means, and means operable upon movement of said stop device out of contact with said pilot valve means to actuate said pilot Valve means to its normal position.

5. A control apparatus comprising, in combination, a source of fluid under pressure, a hopper for receiving sand, a conveyor belt arranged to carry sand over said hopper, a plow for diverting sand from said belt into said hopper, a motor device operable by liuid under pressure to move said plow into diverting relation with said sand and upon release of liuid under pressure therefrom to move said plow out of such relation, a fluid pressure operable vibrator device associated with said hopper for vibrating same, relay valve means having a first position for connecting said source of iiuid under pressure to said motor device and a normal position for disconnecting said source of iiuid under pressure from said motor device and for establishing a communication to convey liuid under pressure from said motor device to said vibrator device, pilot valve means operable to a first position to establish a communication between said source of iiuid under pressure and said relay valve means and operable to a normal position to establish a communication between said relay valve means and atmosphere, and a weighing mechanism for controlling said pilot valve means comprising a scale beam iulcrumed at a point intermediate its ends, a vertically movable sandreceiving basket carried at one end of said beam and disposed beneath said hopper, a stop device carried by said basket adapted to engage said pilot valve means to actuate said pilot valve means to its lirst position, said stop device including a spring adapted to be fully compressed before actuating said pilot valve means to its lirst position, and a counter-weight slidably mounted on said beam at the opposite side of its fulcrum for rocking said beam to lift said basket and said stop device and actuate said pilot valve means to its iirst position, the weight of the load of sand in said basket and of said basket upon preponderance over said counter-weight being operable to rock said beam in the opposite direction and move said basket and said stop device out of contact with said pilot valve means and means operable upon movement of said stop device out of contact with said pilot valve means to actuate said pilot valve means to move to its normal position.

6. A control apparatus comprising, in combination, a source of fluid under pressure, a hopper for receiving sand, a conveyor belt arranged to carry sand over said hopper, a plow for diverting sand from said belt into said hopper, ,a motor device operable by iiuid under pressure to move said plow into diverting relation with said sand and upon release of iiuid under pressure therefrom to move said plow out of such relation, a iiuid pressure operable vibrator device associated with said hopper for vibrating same, relay valve means having a tirst position for connecting said source of fluid under pressure to said motor device and a normal position for disconnecting said source of iluid under pressure from said motor device and for establishing a communication to convey iiuid under pressure from said motor device to said vibrator device, pilot valve means operable to a iirst position to establish a communication between said source of fluid under pressure and said relay valve means and operable to a normal position to establish a communication between said relay valve means and atmosphere, and a Weighing mechanism comprising a scale beam fulcrumed at a point intermediate its ends, a vertically movable sand-receiving basket carried at one end of said beam and disposed beneath said hopper, a stop device carried on said basket and engageable with said pilot valve means to actuate said pilot valve means to its lirst position, and a counter-weight slidably mounted on said beam at the opposite side of its fulcrum and movable to an outermost position to rock said beam to lift said basket and consequently said stop device into engagement with said pilot valve means and movable to an innermost position upon rocking of said beam in response to a preponderance of the weight of load in said basket and of said basket over said counter-weight to move said stop device out of contact with said pilot valve means to actuate said pilot valve means to move to its normal position.

7. Fluid pressure apparatus for controlling operation of a molding sand supply mechanism embodying a plow to divert sand from a movable belt into a hopper through which it is adapted to liow by gravity into a vertically vmovable basket carried by one end of a scale beam ful-- crumed intermediate its ends and upon which a counterweight is slidably mounted longitudinally thereof at the opposite side of its fulcrum, said apparatus comprising in combination, a movable abutment adapted to be connected to said plow and to be operated by tiuid under pressure in a chamber at one side of said movable abutment to move said plow into diverting relation with said sand, means responsive to release of iiuid under pressure from said chamber to actuate said movable abutment to move said plow out of diverting relation with said sand, a fluid pressure operated vibrating device connected to said hopper, valve means operable in one position to supply fluid under pressure to said chamber and in another position to cut off such supply and establish communication between said chamber and vibrator device, and means responsive to the weight of the sand in the said basket for controlling the operation of said valve means.

8. Fluid pressure apparatus for controlling operation of a molding sand supply mechanism embodying a plow to divert sand from a movable belt into a hopper through which it is adapted to flow by gravity into a vertically movable basket carried b y one end of a scale beam fulcrumed intermediate its ends and upon which a counterweight is slidably mounted longitudinally thereof at the opposite side of its fulcrum, said apparatus comprising in combination, a movable abutment adapted to be connected to said plow and to be operated by uid under pressure in a chamber at one side of said movable abutment to move said plow into diverting relation with said sand, means responsive to release of iluid under pressure from said chamber to actuate said movable abutment to move said plow out of diverting relation with said sand, a fluid pressure operated vibrating device connected to said hopper, valve means connected to said chamber and vibrator device responsive to fluid under pressure in a chamber to supply iluid under pressure to the rst named chamber and responsive to venting of the second named chamber to cut ott supply of fluid under pressure to said rst chamber and connect same to said vibrator device, and means controlled and operable by said basket in a full load position thereof to vent the second named chamber and in a substantially empty position thereof to supply uid under pressure to said second named chamber.

9. In a control apparatus, in combination with a sand conveyor belt and a sand hopper, means movable to one position to divert sand from said conveyor belt into said hopper and to another position out of said diverting relation with sand on said belt, a motor device operable by fluid under pressure to move said means to said one position and upon release of iiuid under pressure to move said means to said other position, a uid pressure operable vibrator device associated with and operable by uid under pressure to vibrate said hopper, valve means controlling supply of fluid under pressure to said m-otor device and also operable to establish a fluid pressure release communication from said motor device to said vibrator device for conveying uid under pressure thereto to eiect operation thereof, pilot Valve means, and mechanical means responsive to a certain Weight of sand diverted from said conveyor belt for automatically effecting operation of said pilot valve means to cause the iirst said valve means to cut oif supply of uid pressure to and to release such pressure from said motor device.

References Cited n the le of this patent UNITED STATES PATENTS 2,482,539 Foster Sept. 20, 1949 2,537,005 Brown et al. Jan. 9, 1951