US2679335A

US2679335A - Dribble gate

Info

Publication number: US2679335A
Application number: US211162A
Authority: US
Inventors: Millard J Bell
Original assignee: NEWAYGO ENGINEERING Co
Current assignee: NEWAYGO ENGINEERING Co
Priority date: 1951-02-15
Filing date: 1951-02-15
Publication date: 1954-05-25
Anticipated expiration: 1971-05-25

Description

y25, 1954 M. J. BELL 2,679,335

DRIBBLE GATE Filed Feb. 15 1951 2 Sheets-Sheet l /n venfor M///ar0 J Be// Af fornex y 5, 1954 M. J. BELL 2,679,335

DRIBBLE GATE Filed Feb. 15, 1951 2 Sheets-Sheet 2 /n ven for M///ar0 J Be// Patented May 25, 1954 DRIBBLE GATE Millard J. Bell, Grand Rapids, Mich., assignor to Newaygo Engineering Company, Newaygo, Mich., a corporation of Michigan Application February 15, 1951, Serial No. 211,162

4 Claims. 1

Thi invention relates to dispensers for foundry molding sand and more particularly to an auxiliary gate construction for catching sand which may work its way past the closed primary sand gate of a chute or hopper.

In the handling of relatively finely divided materials such as foundry molding sand, it is customary practice to provide a supply of sand in a hopper from which the sand is withdrawn through a chute or spout. The flow of sand is normally regulated by a pivoted gate having the shape of a segment. The hopper is normally positioned above the mold pattern and the mold is made directly beneath the spout or chute. Often the same hopper is provided with more than one discharge outlet, whereby it may service at least two molding stations. The conventional gates employed to control the flow of sand, even though carefully constructed, frequently permit small quantities of sand to leak past them where the leading edge of the gate contacts the lips of the chute. The sand, normally, will not dribble unless the hopper and chute are subjected to vibration. The operation of one of the sand gates vibrates the entire hopper structure sufliciently to cause sand to dribble past the other gate which may at that time be closed. If the mold has: just been drawn in the mold making station immediately below the closed gate, when this happens, this dribble of sand will ruin the mold. It is the object of my invention to prevent this difficulty.

Although dribble gates or catchers designed to catch and hold this dribble of sand as it leaks past the primary gate have been known for many years, these gates have not been satisfactory. The problem has been the necessity of removing the dribble catcher from beneath the primary gate substantially instantaneously as the primary gate starts to open. Unless the dribble catcher is removed almost immediately, the downrushing body of sand, released by the opening primary gate, will be caused to deflect, causing maldistribution of the sand in the flask below and frequent spilling. At the same time, the dribble gate must be so constructed that it will empty the will be displaced substantially instantaneously as the primary sand gate starts to open, whereby it does not interfere with the stream of sand released from the hopper or chute.

It is a further object of my invention to provide a dribble gate which is effective in catching and holding any sand which may dribble past the primary gate when the primary sand gate is closed.

It is an additional object of my invention to of a sand chute equipped with my dribble gate with both the primary gate and the dribble gate in closed position.

Figure 3 is a fragmentary, side, elevation view of a sand chute equipped with my dribble gate showing the primary gate as it starts to open.

Figure 4 is a fragmentary, side, elevation view of a sand chute equipped with my dribble gate showing the dribble gate in fully opened position and the primary gate in partially opened position.

Figure 5 is a. fragmentary, sectional view taken along the plane of VV of Figure 1.

In executing the objects and purposes of my invention, I have provided a trough or dribble gate pivotally suspended below the end of the primary sand gate where the primary sand gate closes against the sand chute. A cam having a notch or shoulder is mounted on the primary sand which has accumulated in it at the same time the primary gate is opened.

It is, therefore, a primary object of my invention to provide a dribble gate and catcher which sand gate. A pin is mounted on the dribble gate for engaging the notch and cam. The relationship of the notch to the pin is such that as soon as the primary gate starts to withdraw from its closed position the one wall of the notch will force the pin to rotate the dribble gate rapidly into its fully open position. The cam will retain the dribble gate in open position until the primary sand gate is again almost fully closed.

In the following description, I describe my invention as applicable to foundry equipment. This is for convenience only and is not to be considered in any way as a limitation. The handling of foundry sand is its primary purpose, but it will be understood that this is only one possible use which could be made of my invention. My invention is equally usable in almost any situation in which a pivoted gate is used to control the flow of a finely divided, solid material, where it is desired to collect the leakage of material around the primary control gate.

In the following description the terms upwardly and downwardly are frequently used and. are to be taken as meaning upwardly the direction shown in each of the views and downwardly away therefrom. The terms up per and lower are to be considered as synony mous with upwardly and downwardly; respec tively.

Referring now to the drawings in detail, the numeral I indicates a hollow frame orchute.

This chute may be connected to a hopperor any.

other suitable source of molding sand. The chute may itself be merely, the lower end. of a hopper. The molding sand is conducted down the chute l and is released through. the orifice 2 (Figure 4) at the lower end of the .chute.

The orifice 2 is closed by a primary gate 3. The primary gate 3 consists of an arcuate plate 4 and a supporting arm 5 on each end of the plate. Each of the supporting arms 5 is shaped in the form of a segment of a circle. By means of a stud and nut. combination 6,. each ofv the supporting arms 5 adjacent its apex, is vpivotally mounted to the chute I. The plate 4-is shaped on a curve concentric with' the stud and nut combination 6 whereby,,as it is operated,'it will trace a semi-circular path. The endofthechute l is shaped to conform to the plate 4.

The primary gate 3 is actuatedby means of a. rod 1. The rod i is moved by any conventional mechanismsuch as. a handle, solenoid, hydraulic cylinder or similar device. The mechanism for moving the rod 'i'is not shown or described in greater detail. because it is .conventional and forms no part of this invention.

The chute I is provided with a depending lip 8 against which the primary gate 3 is closed. The lipflis preferablyone leg of an. angle element l 1 designed .to support the edge of the hollow frame I against the impact of the primary gate 3 and to maintain a straight edge, and thereby effect a good seal against the edge of the plate 4. The lip 8"also serves to prevent the material fromflowing into .the hereinafter described secondary gate during the initial stages of the opening of the primary gate. It will. be recognized that any other suitable, structural shape may be substituted for the angle element ll.

Nested in the apex of the angle element H is a tube 9 extending thefull length of the angle element. Through the tube 9 .extendsa rod It]. The endsof the rod..l0.extend substantially beyond the, ends of both the tube 9 and the angle element II. The ends of. the rod In support the secondary gate l5. This secondary gate 15 is. the dribble gate or dribble catcher. The secondary gate 15 consists of a shallow, V-shaped trough l6 equipped at .each end withan end plate 11. Eachof the end plates I! has a hole for receiving.the rod Ill whereby the secondary gate 15 is. free to swing about therod I0, the rod l acting as a pivot. The, secondary gate I is held against movement axially'of the rod I 0 by means of the Ventionu cotter pins l8. The length of the secondary gate i5 is such that it will seat over the angle element, including the lip 8, and the primary gate 3.

Closely adjacent the end of the rod ID, a stop or pin I9 is secured to one of the end plates H. The spacing of the pin l9 from the rod [0 is only a short distance. A preferred center to center spacing between these two elements has been found to be about three-quarters of an inch. Some departure from this preferred spacing may be made, but it must not be increased such that the rapid opening of the secondary gate will be seriously delayed This will be subsequently explained under Operation. The pin !9, when the secondary gate is in closed position, is substantially vertically aligned with the rod [0. Again-this is a preferred arrangement and some deviationfrom thisarrangement may be made without affecting theproper operation of my in- Mounted on the primary gate 3, adjacent the leading edgeZfloftheprimary gate 3, is an actuator plate2 I. The actuator plate 2| is provided with an offset 22 (Figuref'l), adjacent the primary gate 3,.whereby the main body. of theactuator plate 2 I. will bealignedwith the pin [9.

The lower surface of the actuator plate. 2-! forms a curved, cam surface 23;" This cam surface traces a curved pathv consisting of. a seg.-, ment of acircle, concentric withithev pivot point of the primary'gate 2, the. stud and nut combinae tion 6. The cam surface 23'is' designedto just clear the surface of. the rod lll'as the primary gate 3 is actuated. By this arrangement, the pin I9 willl'be forced into-substantially horizontal,

alignment with the, rod I0, whenthe primary gate 3 is opened. It will be recognized that shouldit be desired to move thesecondary gate 15 through a still greater arc, the actuator plate 21 can be so designedthat. the cam surface 23 is loweredin relation to the rod W. The necessary minor adjustments in design can bereadilymade to avoid interference between the actuator plate 21' and' the ends ofthe rod lU 'when this modification is desired.

Adjacent therleading. edge 20' of' the primary" gate 3, there is an upwardly extending notch 24" in thecam surface 23."v The wall,25 of the notch 24,.remote from the prima y. sate"3,is substantially perpendicular to the cam. surface 23. The depth and position of the notch is such that'when' both the primary gate3'and secondary'gate l5 are closed, the pin l9'will rest up in the notchin contact with, or substantially in contact with, the wal1.25. It will be understood that this open= ing in the cam surface 23 need not be-a notchy'it may be a step with the wall 25 constituting, the riser. Although the use of the pin l9 andactuator plate 2 I" has been described'only' as existing on one side of the chute I, it:wil1 be recognized that a duplicate structure canabe'providedon the other side of the chute i.

Operation 1 The operation of my invention is relativelysimple. When the-primary'gate 3 andth'e'secondarygate l5 are both closed '(Figure'2), a portion" of the secondary gate I5 is suspendedbeneaththe lip'8 and 'theleadingyedge 'of-"the" primary gate 3'. A sufficient portion of" the trough lfiiprojects. towardthe primarygate 3, beyond the edge of the lip. 8;.jthat it will inter cept any material running down the lip'8j Sincethe wall of; the trough 'l 6;: directly beneath the lip-8;-is inclineddnwardly' toward the center of" the secondary gate, the material will be urged toward the center of the secondary gate [5. The material will be caused to work toward the center of the trough by the same vibration which initially causes the material to leak past the primary gate 3. The secondary gate acts primarily as a small, temporary, storage compartment for the small quantities of material leaking past the primary gate 3.

When the primary gate 3 is to be opened, an pward force is applied to the rod 1, indicated by the arrow in Figure 3. This causes the primary gate 3 to move upwardly and away from the lip 8. The first short movement of the primary gate 3 forces the wall against th pin 19, causing the pin it to pivot about the rod it (Figure 3). Since the wall 25 is substantially perpendicular to the cam surface 23, when the primary gate 3 has moved only a very short distance in its opening stroke, the pin is has already been pivoted into a position substantially in horizontal alignment with the rod Hi. This forces the secondary gate completely out of the way of the stream of material being released by the primary gate 3 and at the same time empties the accumulated material from the secondary gate l5 (Figure 4). Since only a portion of the secondary gat [5 projects beyond the lip 8 into the path of the material, the secondary gate i5 is entirely removed from the path of this material, when the pin l9 has pivoted only a very short distance (Figure 3).

The cam surface 23 maintains the secondary gate in open or discharge position throughout the initial opening movement of said primary gate 3 in its opening and closing operations (Figure 4). When the primary gate 3 is being closed, the cam surface 23 and the wall 25 maintain the secondary gate E5 in discharge position until the primary gate 3 is substantially entirely closed. This delay of the closing of the secondary gate I5, is as essential as the rapid removal of the secondary gate when the primary gate 3 is opened. Unless the closing of the secondary gate is restrained until the flow of material from the chute l is stopped, it will become filled and will have no capacity for holdin the material leaking past the closed primary gate.

It will be observed that minor variations may be made in the structure and arrangement used to carry out the principle of my invention which will not impair the rapid action of opening and closing the secondary gate and the timing of its operation in relation to the primary gate. Each of these changes will not affect the principle of my invention and are to be considered as included in the hereinafter appended claims unless the language of these claims states specifically to the contrary.

I claim:

1. In gate construction for a device having a chute and a discharge opening at the end of said chute, the combination comprising: a primary gate pivotally mounted on said chute; a secondary gate below said primary gate constituting a shallow trough and actuated by said primary gate; a plate at each end of said trough; means for pivotally mounting each of said plates to said chute; a pin on one of said plates, said pin being above said pivotal mounting means when said secondary gate is in closed position; an actuator plate mounted on said primary gate and projecting away from said primary gate above said secondary gate in a direction opposite to the direction of movement of said primary gate when said primary gate is opened; said actuating plate having a cam surface tracing an are substantially concentric with said pivotal mounting for said primary gate; and a notch in said cam surface adjacent said primary gate for receiving said pin, said pin being immediately adjacent the wall of said notch remote from said primary gate when said primary gate is closed.

2. In gate construction for a device having a chute and a discharge opening at the end of said chute, the combination comprisin a primary gate pivotally mounted on said chute; a secondary gate below said primary gate constituting a shallow trough and actuated by said primary gate; a plate at each end of said trough; a pivot for swingably mounting each of said plates to said chute; a stop on one of said plates closely adjacent said pivot, said stop being above said pivot when said secondary gate is in closed position; an actuator plate mounted on said primary gate and projecting away from said primary gate above said secondary gate opposite to the direction of movement of said primary gate when said 7 primary gate is opened; said actuating plate having a cam surface directed toward said secondary gate and tracing an are substantially concentric with said pivotal mounting for said primary gate; and a notch in said cam surface closely adjacent said primary gate for receiving said stop; the wall of said notch facing said primary gate being substantially perpendicular to said cam surface and in contact with said stop when said primary gate is closed whereby the initial openin movement of said primary gate will positively pivot said secondary gate through its entire arc of travel.

3. In gate construction for a device having a chute and a discharge opening at the end of said chute, the combination comprising: a primary gate pivotally mounted on saidchute; a secondary gate below said primary gate constituting a shallow trough and actuated by said primary gate; a plate at each end of said trough; a pivot for swingably mounting each of said plates to said chute; a pin on one of said plates closely adjacent said pivot, said pin being above said pivot when said secondary gate is in closed position; an actuator plate mounted on said primary gate and projecting away from said primary gate above said secondary gate opposite to the direction of movement of said primary gate when said primary gate is opened; and said actuating plate having a cam surface directed toward said secondary gate and having an indented shoulder immediately adjacent said primary gate; said cam surface tracin an arc substantially concentric with said pivotal mounting for said primary gate; the riser wall of said shoulder facing said primary gate being substantially perpendicular to said cam surface; said pin resting against said riser wall when said primary gate and said secondary gate ar each in closed position whereby the initial opening movement of said primary gate will positively pivot said secondary gate through its entire arc of travel.

4. In a gate construction for a device having a chute and a discharge opening at the end of said chute, the combination comprising: a depending lip on said chute along one side of said opening; a primary gate pivotally mounted on said chute for alternately opening and closing said opening; said primary gate in closed position engaging said lip; a trough shaped secondary gate pivotally mounted on said chute adjacent said primary gate andextending beneath said lip and said primamzgateg-whenizbothzsaid primary gate .andrri ffom'zsaid prlmarygatabeingmhan; acute Angle? said secondary gate: are:c1osed;'; a; pina on :said. seer to said cam surface:

ondany-gata abuve saidmivotalmounting ofisalidn secondary gate: to :said 'nhutm an" actuatorv plate,- Referenoes--flited an, .the -fi1e: of this patent: mounted Hon said: primary; gate" and :proj eating 5 UNITED; STATES PATENTS; mi-imm:said px'imanry gate alcovesaidasecondv;

ary gate; said actuator platehaving azcamsunfig s flgg No 23 facfi fficing said:SBcOndary- :gatmand-:tmcing an 1 f c w r 2 it arm-substantiallyconcentric; WithLSELidJDiVOtaI J 1'492l937 ig fig; o i

m mung 53 pnmary gate and 3 2,332,817 Hertnch;; v ,,Dec. 28, 19.43..

said-"cam surface-adjacent saimprimary gate for: receiving saidmm; the mall? of. said notch remotes-