US2750122A - Apparatus for kitchen waste grinders - Google Patents

Description

June 12, 1956 G. w. QUAST 2,750,122

APPARATUS FOR KITCHEN WASTE GRINDERS Filed Sept. 21, 1951 3 Sheets-Sheet l E9 11 n; 50 3 3| GILBERT W.QUAST INVENTOR.

BYW/LZQmaqfi ATTORNEY APPARATUS FOR KITCHEN WASTE GRINDERS Filed Sept. 21. 1951 3 Sheets-Sheet 2 29 GILBERT w. QUAST INVENTOR.

m'idwf A TTORNE Y June 12, 1956 G. w. QUAST APPARATUS FOR KITCHEN WASTE GRINDERS 3 Sheets-Sheet 3 Filed Sept. 21, 195] FIG. IO.

GLBERT W. QUAST INVENTOR.

BY ATTORNE invention provideswnot only United States Patent Oil 2,750,122 APPARATUS FOR KITCHEN Gilbert We Quast, Belt-Company,

cousin It has heretofore been a domestic grinders, "to

minimum flow of water passing through the water supply conduit supplying water to the: grinder. Such an installation is shown in U. '8. Patent -No. 2,244,402 issued June 3, 1941. Thexpresent that a predetermined mini- 2,750,122 Patented June 12, 19.56

ice

overcomeethis danger, a vent to the and this same vent,

the grinder, as previously explained.

Other objects and advantages of the invention will become apparent from the following detailed description and theaccompanying drawings, wherein:

Figure l is a side elevation showing the grinder and one embodiment of the feeding mechanism as mounted under a kitchen table;

Fig. 2 is an enlarged side elevation of thefeeding portion. of themechanism shown in Fig. l, with portions broken away;

Fig; 3 is an end elevation of the apparatusshown in Fig. 1-with .certain parts broken away and the-electrical control system diagrammatically illustrated;

Fig. 4-is a section taken on line 4- 4 of Fig, 3;

Fig. 5 is a section taken on line 5-5 of Fig. 3;

Fig. 6 is a plan view taken from above the apparatus shown in Figs. 1, 2 and 3;

Fig. 7 is an inverted plan view of the feed inlet cover plate showing details of the underside of this plate;

view of the cover plate shown in Fig. 7 with the plate turned right side up and in position-at the topvof the feeding stack;

event thefeed stack cover plate is removed;

Fig. 10 is a top plan view of the apparatusshown in Fig. 9; and

Fig. 11 is a flow diagram of the hydraulic control may be h'it'and damaged by dish trays other kitchen utensils.

Waste or garbage is fed to the machine down an inclined-chute 21, having an inclined bottom'22 and vervisual indication of such plugging.

As is readily apparent from the drawings, the feed stack 25 is made in two sections, an upper portion 30 and a lower portion '31, and communicates at its bottom with a grinder 32 which is driven by an electric motor The successful disposal of kitchen w s er q fi acting control of the Water supplied to the grinder to fa- -holes 42 and into one cilitate the grinding operation and also exacting control of the water supplied to the com inuted matter to render it sufficiently fluid to fiow easily through the sewer connection. The aforesaid conditions are c ustomarily satisfied by insuring that a predetermined minimum flow of water is maintained, but applicant has discovered that it is also necessary that a predetermined maximum flow of water should not be exceeded if maximum grinding efficiency is to be achieved, and if the maximum ratio of solids to fluid in the sewage is to be obtained. The novel water control system now to be described provides an accurate control of both minimum and maximum flow and for these objectives employs components positive in operation and requiring a minimum of maintenance.

Water is conducted to the apparatus through a pipe 37 and valve 38 (see Fig. 3). When the valve 38 1s open water flows through a flow switch 39, an example of which is described in detail in U. S. Patent No. 2,244,373 issued June 3, 1941. Briefly, this flow switch 39 contains a piston which is actuated when water is fed through the switch mechanism, and as long as a predetermined minimum flow of water passes through the switch the piston is held in a position wherein it makes an electrical contact which may be used for controlling a motor. Should the flow of water fall below said predetermined minimum quantity, then the piston falls back and the electrical connection is broken, thus stopping the motor. In order to insure that the predetermined minimum quantity of water flows through the switch 39, the normal flow therethrough is in excess of the said minimum quantity.

The usual practice is to allow a considerable excess over the predetermined minimum quantity to flow so that the switch 39 will not cut in and out if the flow fluctuates due to the turning on and off of other water taps on the main supplying the grinder.

A pipe 40 leads from the outlet side of the flow switch 39 and connects with a header pipe 41 having holes 42 in its underside through which water may be discharged. The header pipe 41 is dead-ended at 43 by a plug 44 or other convenient means.

Water entering the header pipe 41 falls through the leg 45 of a trough or reservoir 46 which surrounds three sides of the upper portion 30 of the feed stack 25. It should be noted that the water falls through an air gap between the header pipe 41 and the trough 46, which air gap prevents the formation of any back pressure within the apparatus that might cause a reverse fiow of waste matter into the fresh water supply line. There are two outlets tion of the trough 46, one of which (47) communicates with the top of a vertical vent 49, which vent communicates at its lower end with the underside of the grinder 32 and the sewer outlet 36 and is arranged to lie along one side of the feed stack 25. The second outlet 48 in the trough 46 communicates with a cup 50 on one side of the lower portion 31 of the grinder feed stack 25, which cup at its lower end communicates with an orifice 51, which in turn communicates with the interior portion of the grinder feed stack 25, at a point above the grinder rotor.

The trough 46 is divided into two sections by a weir 52, one of said portions 53 containing the outlet 47 to the vent 49, and the other portion 54 containing the outlet 48 to the cup 50.

In operation, water flows into the portion 54 of the trough 46 from the header pipe 41 at a minimum rate of flow in excess of that required to operate the fiow control switch 39. The portion 54 of the trough fills with water until the water level reaches the top of the weir 52. When this condition obtains, water spills over the weir into the portion of the trough 53 containing the outlet to the grinder discharge. It should be noted that this outlet 47 is considerably supplies water through the cup 50 grinder proper, and the size of the opening and orifice 51 to the 47 is preferlarger than the outlet 48 which 47 and 48 in the lower por- I rotor 34 rotates.

ture and the dotted t my imam? \g ass substantially ll of the wa e which can be delivered by the header pipe. h\\\ level of water in the trough, after reaching a height sl1ght-- ly greater than that of the weir 52 remains substantially at that level, and a fixed portion of the water feedsthrough the orifice 51 into the grinder to facilitate the: comminution of waste matter, any excess flow above said: fixed portion being by-passed down the vertical vent 49.. The fixed quantity of water fed to the grinder chamber is accurately metered by the orifice 51, which is acted upon by the fixed head of water determined by the weir' 52, and therefore the maximum flow determined by the. height of the water head and the size of the orifice 51 is: never exceeded. This feature assures the presence in the grinding chamber of the proper amount of water to fa-- eliminates the usual cilitate most efiicient grinding, and

grinding etfi-- difliculty of an excess of water reducing ciency.

Water in excess of this predetermined maximum is by-passed through the outlet 47 and vent 49 to the sewer outlet 36. It should be noted that the vent 49 commune cates directly with the underside of the perforated grate: 35, through which comminuted matter is discharged fromthe grinder. Thus, water by-passed as being in excess of the maximum amount to be fed to the grinder performs: a useful function in flushing the chamber into which comminuted matter is discharged by the grinder, and this water also renders the comminuted garbage more fluid so that there is less tendency for the drain or sewer to become clogged.

It is possible in a waste disposal apparatus of the typeherein illustrated, for the grinder to act as a pump and cause a momentary reverse flow from the sewer drain back up through the feed stack. This condition is caused by a stoppage in the feed stack permitting the rapidly rotating grinder rotor to draw a partial vacuum in said feed stack, which feed stack then becomes the suction side of a pump and the result is a back flow from the sewer. To eliminate this pump action, the vent 4? is made large enough to handle the water passed throughit without being completely filled. Thus the vent 49 serves as a vent to the atmosphere and assures the main-- tenance of atmospheric pressure in the grinder chamber, which results in the elimination of the aforesaid pumping action.

It has been observed that grinders of the type herein illustrated do not discharge all of the comminuted matter through the grate 35 on the first pass of the rotor 34, and therefore a slight build-up of comminuted matter may be detected around the area 55 in the grinder feed stack, having been thrown there centrifugally as the toothed Accordingly, the orifice 51 has been located on the opposite side of the feed chute 31 in a position to discharge a stream of water which will impinge in the area 55 on the wall of the feed stack where the comminuted matter tends to collect. An effective flushing action is thus provided which substantially removes any comminuted matter adhering to the inside walls of the feed stack 31.

Figs. 6, 7 and 8 best illustrate the novel features of the cover plate 27 which forms a closure for the open top 28 of the feed stack 25. It is essential for the safety of the operator that such a closure be provided over the top of the feed stack as a protection against flying particles thrown off by the toothed rotor 34. There are times, however, when due to the quantity or quality of the waste matter fed to the grinder, the feed stack may become clogged. Under such conditions, it may be necessary to prod or poke the garbage into the rotor 34. .In order to permit such poking, the cover plate 27, may be partially removed or retracted, thus providing an opening large enough to permit the entry of a poking stick. Figs. 6, 7 and 8 illustrate the construction which provides this fealine position in Fig. 6 illustrates th cover plate in this partially retracted position.

"Water conduit 70 when thepressurein said conduitreaches.apredeterrnined 5 A'fiixed to the underside oftheecover' plate 27 are two straps "56-and 57 (see Fig. 7 and 8)"WhlhCa1Tythe hinges 58" from which the swinging door 26-is-piv0ted. One of the-rearmost corners59- oftthe strap 56' is bent down to form a stop. Projecting through the side of ;the-upper-portionof the feed stack 25"and aligned with said-stop 59 isa rod 60 formed with a handle portion-61 at its outermost end. The rod 60projects within-the said stack enclosure asufiicientdistance to engage the stop-59 and-thus limits the extent'to wh'i'c'hthe-cover plate 27 may be retracted for the admission-of" a-poking stick. Retrac tion is eliected along a track and trackway connection formed -by the cover plate 27, thestraps 5'6 "and 57 and afiange bordering the opening 28 in the 'top of the feed stack 25, as illustrated in Fig. '8.

In "order to facilitate complete removal of the cover -plate'27 for cleaning-the interior of the feed stack, the rod 60 may be withdrawn against the pressure of astrip spring 62by means 'ofthe handle'6'1 until it no longer engages the stop 59 and in this position of therod the cover plate "27' and swinging door '26 may be' removed as a unit by sliding-it until the-track and trackway connection' moves out of engagement.

I-n'order toprevent the possibilityof'the operator reaching into the feed stack while the grinder is in operation, a normally open switch 63, connected 'in'series' with the holding coils of a magnetic starter 63 is provided as shown-in the wiring diagram of Fig. 3. This switch is actuated through 'a linkage'by 'a button 64 located beneath the "cover plate 27 in a position where it is depressed'by' a'bent down'portion 57' of the strap 57 when the cover plate-is in any position at the top of the feedstack 'betweencompletely closed and the partially-retracted ,posi- *tion determined by engagement of the stop '59 and the rod -6'0. The switch returns to its normally open position when the handle Gris pulled and the 'coverplateis opened "or retracted beyond the aforesaid partially retracted position. 'When the button 64 is released, the-switch 63 opens andthe'motor stops. In order for the motor to be operated, the cover plate 'must" be in position over the top of the feed stack so that it depressesthe button .64 and-closesthe switch 63.

Figs. 9, and 11 illustratetasecond embodiment of the water control features'of the invention and this embodiment contains several novel features. 7

In Fig. 9 water enters through a supplycondu'itflfland aconsta'nt how-valve 71. The details of .the construction of a constant fiowvalve of the type herein illustrated are described in U. S. Patent No. 2,454,929 issued Novem- "ber 30, 1-948. Briefly, this valve containsa rubber .annulus providing an orifice through which water may pass. The' rubber annulus functions .to provide an orifice of varying cross section in response to pressure variations inthe supply line 70; "I11us, if .a pressure surge occurs in'the supply conduit, the rubber annulus'is deformed-and the orifice becomes smaller. In thismanner, a constant "flow throgh the valve is maintained irrespective of pressure variations in the supply conduit 70. This feature *is'very important in an apparatus of the-type herein disclosed because such apparatu is usually employed in an establishment having numerous appliances utilizing water. As the 'valves controlling the watersupply to these appliances are opened and closed, pressure variations and surges are created in the supply conduit. The constant *fiow'va-lve "I1 admits more water than the minimum requiredtoroptimumgrinding.

A pressure switch 72is connected to the conduit70 on nlie-outputiside of'theconstant flow-valve71. 'This'switch is o'f a=common type readily available and well'kno'wn in titre iart and: its :function is. to actuate an electrical switch in response to a predetermined pressure condition in-the Thus, the switch'is' 'actu'a'ted only minimum amount, and should the pressure 'fall' below "electrical circuit controlled 'by the pressure switch is opened. Beyond the=pressure swith-'72,*the 'water supply source connects With'fi straight "vertical conduit" 78 which in turnconnectsat itsupper end "with a header74' having an opening '75 in its lower portion through Which=water may be discharged into the trough 46, from whence water flows to the grinder and-to the drain outlet as previouslydescribed in connection with Fig. 3. 'The pressure switch 72 insures that the grinder will not operate unless the aforesaid pressure condition obtains in the grinder fluid supply.

At the lowermost end of the vertical conduit'73' an orifice 76 :is inserted in the conduit to provide a restricted 27 is a U-shaped bracket 79 having holes in its legs through which is passeda'partially threaded rod 80. The cover plate'zTzrnay be partially opened for theadrnission of a :po'hin'g stick, the limit of such opening being con trolled by the abutment of Y bracket 79 with the head 81 of 'the rod -80. Sliding movement of the cover plate 27*is :along a track and trackway connection as previously described in connectionwith Fig. 3. In order to completely remove the cover plate/it is necessary firstto' opensaid cover-plate until the brac'ket 79"abut-s the head 81 ofthe screw 8%, thereby partially'exposingthe entrancetothe feed stack 25. In this position it 'is possible'for'the 'operator to reach through the opening andto turn a knurled knob 82 which is afiixed to the rod 86. As this knob is turned, the rod 80, "which is threaded into header 7 4, backs off to the right in 'Figs. 9, 1'0 and 11 and relieves a piston 83, which is reciprocably contained within a cylindrical opening 84in the header 74. At the'left hand end of the piston '83 (Fig. 9) is affixed the movable portion '35 of thevalve 78. As the rod is backed off and the piston is-freed to move, this movable portion. of" the valve is forced away from the valve seat 86 by the .pressure ofspring'87 and water flows from'the by-passconduit '77 into the header '74 and in turn into'the troug'h46 with which it communicates (as shown in Fig. 10). From thetrough46'water flows to the drain and into the grinder as previously described; With the valve78 thus open, the major portionof the water, taking thepath of least resistance, flows through the bypass conduit '77, instead of through conduit 73. This by-pass of the water reduces the flow through orifice 76 and thereby reduces the pressure in the line below the pointat which the pressure switch 72 is set to operate and thus stops the grinder motor.

in order to restart the grinder it is necessary toreplace the cover plate 27 and tighten the rod until'itforces piston 83 to reseat'the movableiportion of the valve/78, in which condition pressure is again restored because of the passage of water through the orifice -76. It should be noted that the rod .80 is of a small diameter and that it does not engage the piston 83 until it has traveled in wardly a substantial distance, thereby making it impossible for an'operator to cheat the safety device by insert ing his finger into the threaded portion of the header 74. Also, it should be noted that the valve 78 opens immediately upon the rod 80 beingbacked ofif and that, .therefore, the grinder is stopped a substantial timebefore-the operator is able v to'comp'letcly :back votf the .rod 80- .until it 'releasesfro'm the header 74 thereby enabling-the re- II 10Val Of the cover plate 27. This-feature allows sulfi- -c1ent time after'the interruption of the electrical circuit to the grinder motor for the grinder to coast to a stop beplate and insert his hand into the feed stack.

Modifications and equivalents of the above described embodiments of the invention will undoubtedly be apparent to those skilled in this art and it is the intent that the scope of this invention, therefore, be limited not by the description thereof but only by the clear import of the following claims. I claim:

1. In a waste disposal apparatus having a grinder and an electric motor for driving said grinder; a chamber encasing said grinder, said chamber having a discharge portion connectible with a drain outlet and arranged to receive ground waste from said grinder; a hopper arranged to receive waste matter for disposal and pass the same to the grinder; a primary fluid supply circuit having a valve and through which fluid may be supplied to said hopper to facilitate grinding and the flushing of ground matter into said drain when said valve is opened; an electrical circuit operatively associated with said motor and said primary fluid supply circuit; a normally open switch in said electrical circuit; switch-closing means adapted to close said switch only when an adequate predetermined quantity of water per unit of time is supplied by said primary fluid supply circuit; a branch fluid supply circuit connected with said chamber discharge portion and said primary fluid supply circuit on the downstream side of said switch-closing means, and fluid metering means peratively connected with said primary fluid supply circuit and said branch fluid supply circuit limiting to a predetermined maximum the quantity of fluid flowing into said hopper irrespective of the extent to which the aforesaid valve is opened and by-passing excess fluid above said maximum to the casing discharge portion through said branch fluid supply circuit.

2. In a waste disposal apparatus having a grinder and an electric motor for driving said grinder; a chamber encasing said grinder, said chamber having a discharge portion connectible with a drain outlet and arranged to receive ground waste from said grinder; a hopper arranged to receive waste matter for disposal and pass the same to the grinder; a primary fluid supply circuit for supplying fluid to said hopper to facilitate grinding and the flushing of ground matter into said drain; an electrical circuit operatively associated with said motor and 7 said primary fluid supply circuit; a normally open switch in said electrical circuit; switch-closing means adapted to close said switch only when an adequate predetermined quantity of water per unit of time is supplied by said primaryfluid supply circuit; means in said primary fluid supply circuit maintaining a substantially constant fluid flow therethrough irrespective of fluid pressure variations; a branch fluid supply circuit connected with said chamber discharge portion and said primary fluid supply circuit on the downstream side of said switch-closing means; and fluid metering means operatively connected with said primary fluid supply circuit and said branch fluid supply circuit limiting to a predetermined maximum the quantity of. fluid flowing into said hopper irrespective of the quantity of fluid flowing through the aforesaid primary supply circuit and bypassing excess fluid above said maximum to the casing discharge portion through said branch fluid supply circuit.

3. In awaste disposal apparatus having a grinder and an electric motor for driving said grinder; a chamber encasing said grinder. said chamber having a discharge portion connectible with a drain outlet and arranged to re- 'ceive ground waste from said grinder; a hopper arranged 'to'receive waste matter for disposal and pass the same to the grinder; a primary fluid supply circuit including a valve which may be opened for supplying fluid to said hopper to facilitate grinding and the flushing of ground matter into said drain; an electrical circuit operatively associated with said motor and said primary fluid supply circuit; a normally open switch in'said electrical circuit; switch closing means adapted to close said switch only in response to a predetermined minimum fluid flow per unit of time through said primary fluid supply circuit, said flow being in excess of the grinders minimum requirements; a branch fluid supply circuit connected with said chamber discharge portion and said primary fluid supply circuit on the downstream side of said switch closing means; and fluid metering means operatively connected with said primary fluid supply circuit and said branch fluid supply circuit limiting to a predetermined maximum the quantity of fluid flowing into said hopper irrespective of the extent to which said valve is opened and by-passing excess fluid above said maximum to the casing discharge portion through said branch fluid supply circuit.

4. in a' waste disposal apparatus having a grinder and an electric motor for driving said grinder; a chamber encasing said grinder, said chamber having a discharge portion connectible with a drain outlet and arranged to receive ground waste from said grinder; a hopper arranged to receive waste matter for disposal and pass the same to the grinder; a primary fluid supply circuit for supplying fluid to said hopper to facilitate grinding and the flushing of ground matter into said drain; an electrical circuit operatively associated with said motor and said primary fluid supply circuit; a normally open switch in said electrical circuit adapted to close only in response to the passage of a predetermined minimum quantity of fluid per unit of time through said primary fluid supply circuit; a branch fluid supply circuit connected with said chamber discharge portion and said primary fluid supply circuit on the downstream side of said switch; fluid metering means comprising a reservoir, a weir for controlling the fluid level in said reservoir, an orifice communicating with said reservoir and said hopper whereby the fixed head of fluid standing on said orifice limits the maximum fluid flow to said hopper when the flow in the primary fluid supply circuit exceeds said maximum flow and means lay-passing fluid flow in excess of the aforesaid maximum through said branch supply circuit to the casing discharge portion.

5. In a waste disposal apparatus having a grinder; a chamber encasing said grinder, said chamber having a discharge portion connectible with a drain outlet and arranged to receive ground waste from said grinder; a hopper arranged to receive waste matter for disposal and pass the same to the grinder; a primary fluid supply circuit for supplying fluid to said hopper to facilitate grinding and the flushing of ground matter into said drain; means in said primary fluid supply circuit limiting to a predetermined maximum the fluid flow through said circuit, said maximum flow being in excess of the amount required for grinding; a branch fluid supply circuit connecting said chamber discharge portion and said primary fluid supply circuit; and fluid metering means operatively connected with said primary fluid supply circuit and said branch fluid supply circuit limiting to a predetermined maximum the quantity of fluid flowing into said hopper irrespective of the flow in the primary fluid supply circuit and bypassing excess fluid above said last mentioned maximum to the casing discharge portion through said branch fluid supply circuit.

6. In a waste disposal apparatus having a grinder; a water supply conduit, a discharge outlet for ground waste communicating with said grinder, means assuring the supply of a predetermined minimum quantity of water per unit of time through said supply conduit as a condition of grinder operativeness, means communicating with said grinder and said water supply conduit for supplying water to the grinder to facilitate the disposal of waste, means controlling the flow of water to the grinder irrespective of the flow in the aforesaid supply conduit so that a predetermined maximum flow is not exceeded, and means providing discharge of any excess water above said predetermined maximum.

7. In a waste disposal apparatus having a grinder a1- ranged-to *comminute matter-in a grinding chamber; a water-supplyconduit, adischarge-outlet for groundwaste communicatingwithsaid grinding chamber, means communicating with said *grinding'chamber and said water supply conduit forsupplyingwater to'the-grinder to facilitate the disposal of waste, said'lastmentioned means'controlling the flow of water to the grinding chamber so that a predeterrninedmaximumflow is not exceeded irrespective of the flow intsaid Water supplycondnit, and means by -passing, any excess water above-said predetermined maximum around said grinding chamber for discharge through said discharge outlet.

'8. A fluid, supply system for a wastetdisposal apparatus of the type having a grinder with a wastetoutlet connectible to :a drain and an inlet for waste to be ground comprising: a conduit connectible to a source of fluid supply, means assuring the supply of a predetermined flow of fluid through said conduit as a condition of grinder operativeness, anti-siphon means for preventinga-reverse fluid flow through said conduit, a reservoir adapted to receive fluid from said conduit, means controlling the level of fluid in said reservoir providing a fixed head, an orifice communicating with said reservoir and said waste inlet whereby the fixed head of fluid and the configuration and size of said orifice limit to a predetermined maximum the fluid flowing to said grinder through the waste inlet irrespective of the fluid flow through the aforesaid supply conduit, and means communicating with said waste outlet and said reservoir for by-passing fluid above said predetermined maximum for discharge through said waste outlet.

9. A fluid supply system for a waste disposal apparatus of the type having a grinder with a waste outlet connectible to a drain and an inlet for Waste to be ground comprising; a conduit connectible to a source of fluid supply, means limiting the fluid flow through said conduit substantially to a predetermined maximum in excess of the grinders requirement, means rendering said grinder operative only during the existence of a predetermined minimum fluid pressure in said conduit, anti-siphon means for preventing a reverse fluid flow through said conduit, a reservoir adapted to receive fluid from said conduit, means providing a maximum fluid level in said reservoir, an orifice communicating with said reservoir and the waste inlet and adapted to control the flow of fluid from the reservoir to the waste inlet whereby the configuration and size of the orifice and the maximum fluid level in said reservoir limit to a predetermined maximum the fluid flowing to the waste inlet irrespective of the quantity of fluid flowing through the aforesaid conduit, and means by-passing fluid in excess of said predetermined maximum for discharge through said waste outlet.

10. In a waste disposal apparatus having a grinder; a conduit providing a substantially straight passage to said grinder and adapted to receive waste for disposal, said conduit being open at an end removed from said grinder and having a second opening laterally disposed in one side; a unitary closure member for said openings comprising a first plate adapted to removably overlie the first of said openings, a second plate adapted to overlie the second opening, and a pivotal joint connecting said first and second plates; a track and trackway connection for removably and reciprocably joining said closure member to said conduit whereby one of said plates may close or partially expose the open end of the conduit for the admission of a prodding instrument and the other plate may cover the other opening or be pivoted away from the opening for the admission of waste matter, and the closure member may be completely removed from the conduit as a unit.

11. Apparatus according to claim 10 in which the pivotally mounted plate has a portion thereof bent back to form a vent to the interior of the conduit.

12. In a waste disposal apparatus having a grinder and an electric motor for driving the grinder; an electric circuit operatively associated with said motor; a hopper 10 communicating with said grinder and arranged to com tain-waste matter for diSPOSBILSH-iCThOPPfiI' having anopening; a liquidsupply conduit communicating -with=said hopper for supplyingfluid to aid in the grinding and flushing of waste matter; a movable member arranged tozv extend across the opening in said hopper, said-member being movable'rfrom aposition substantially blockingsaid 'hopper opening to a position exposing said opening; a--'normally open switch in said electrical circuit responsive to the fluid pressure'in said conduit and means for-selectively decreasing the fluid pressure in said conduit; saidlast mentioned means being operative toperm'it norrnalfluid pressure insaid conduit whereby to close said switchzand energize the electric motor when said movable member is in the aforesaid position substantially =blocking=the hopper opening and toreduce the fluid pressure--below normal whereby to open the switch and interrupt the electricalcircuit to-said motor whenthe member is moved to aposition exposingthehopper opening.

13. Ina waste disposal apparatus having a "grinder'an'd an electric motor for driving the grinder; an electric circuit operatively associated with said motor; a hopper communicating with said grinder and arranged to contain waste matter for disposal, said hopper having an opening; a removable closure member for the opening in said hopper, said closure member being freely movable from a position substantially covering said hopper opening to a position partially exposing said opening whereby a prodding instrument may be inserted through said partially exposed opening for prodding waste matter from the hopper into the grinder; a primary fluid supply conduit for supplying fluid to said hopper to facilitate grinding; a pressure-responsive switch operatively associated with said primary conduit and said electric circuit whereby the electric motor is energized only in response to a predetermined minimum pressure in said primary conduit; a normally inoperative branch fluid supply circuit operatively associated with said primary fluid supply circuit; a valve in said branch supply circuit whereby the circuit may be rendered operative when said valve is open; means dividing the fluid flow between said primary and branch fluid supply circuits whereby the aforesaid predetermined minimum pressure may be maintained when said branch fluid circuit is inoperative and may not be maintained when the branch circuit is operative; and interlocking means maintaining the valve in closed position while permitting limited movement of the closure member as aforesaid, said interlocking means being releasable to permit greater movement of the closure member and simultaneously effecting opening of the valve.

14. Feeding apparatus for grinders adapted for use with a work table comprising; a substantially vertical conduit communicating with the grinder, said conduit having an open top arranged to be substantially flush with the top of the table and a lateral opening extending downwardly on one side of the conduit, a feed chute having sides diverging outwardly and a bottom surface inclined upwardly from the margins of said lateral opening, the outer end of said inclined surface and the sides of said chute merging with the top of the table, and a cover plate slidably mounted over the open top of said conduit and having a door hingedly mounted thereon which may overlie the lateral opening in the conduit.

15. Apparatus according to claim 10 having an electric motor for driving the grinder and an electric circuit operatively associated with said motor; an abutment carried by the closure member engageable with a cooperating abutment carried by the conduit, said abutments serving to limit the extent of movement of the closure member from a position completely closing the first opening to a position partially exposing said opening for the admission of a prodding instrument when the first plate of said closure member is in position to close the open end of the conduit, one of said abutments being movable to a position not limiting the movement of the other abutment whereby the movable member may be completely removed; and a normally open switch in said electrical circuit arranged to be closed by the presence of said closure member in any position from the aforesaid position completely closing the first opening to the partially open position determined by engagement of the abutments and to remain open when said closure member is opened past said last mentioned position.

16. Apparatus according to claim 10 having an electric motor for driving the grinder and an electric circuit operatively associated with said motor; an abutment carried by the closure member engageable with a cooperating abutment carried by the conduit, said abutments sewing to limit the extent of movement of the closure member from a position completely closing the first opening to a position partially exposing said opening for the admission of a prodding instrument when the first plate of said closure member is in position to close the open end of the conduit, one of said abutments being movable to a position not limiting the movement of the other abutment 12 whereby the movable member may be completely removed; and a normally open switch in said electrical circuit arranged to remain closed when the said abutments are in position to limit the movement of the closure'member as aforesaid and to remain open when said closure member is freed for removal.

References Cited in the file of this patent UNITED STATES PATENTS 1,659,499 Sedberry Feb. 14, 1928 1,965,033 Dillon July 3, 1934 2,105,759 Stevenson Jan. 18, 1938 2,185,037 Powers Dec. 26, 1939 2,244,402 Powers June 3, 1941 2,426,346 Feight Aug. 26, 1947 2,442,812 Jordan June 8, 1948 2,454,929 Kempton Nov. 30, 1948 2,536,372 Jordan Jan. 2, 1951 2,536,928 Hammell Jan. 2, 1951

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