US2786210A - Apparatus for automatically flushing urinals at varying intervals - Google Patents

Description

March 26, 1957 FRASER 2,786,210

APPARATUS FOR AUTOMATICALLY FLUSHING URINALS AT VARYING INTERVAL-S 4 Sheets-Sheet 1 Filed Dec. 29, 1953 INVENTOR LEA/IE6 Pie/1629A Jaw aw ATTORNEY March 26, 1957 J. FRASER 2,786,210

APPARATUS FOR AUTOMATICALLY FLUSHING URINALS AT VARYING INTERVALS Filed Dec. 29, 1953 '4 Sheets-Sheet 2 J 15 6 I i.- I J '1 ,1 l, 4 :1" f: Q Ill 5% I 42 .55 v q I A INVENTOR ATTORNEY March 26, 1957 J. FRASER 2,786,210

APPARATUS FOR AUTOMATICALLY FLUSHING URINALS AT VARYING INTERVALS Filed Dec. 29, 1953 4 Sheets-Sheet 3 FIG. 4.

6Q s o INVENTOR BY r 62 5 ATTORNEY J. FRASER 2,786,21Q

APPARATUS FOR AUTOMATICALLY FLUSHING URINALS AT VARYING INTERVALS March 26, 1957' 4 Sheets-Sheet 4 Filed Dec. 29., 1953 2 .5 4 5'6 FIE. 6;

1 1 AT i; F g

L I w Llj | ET Lil L1! INVENTQR $14455 fiemaz I I II. I, ATTORNEY United States Patent APPARATUS FOR AUTOMATICALLY FLUSHING URINALS AT VARYING INTERVALS James Fraser, Wilmington, Del., assignor to Spealrman Company, Wilmington, DeL, a corporation of Delaware Application December 29, 1953, Serial No. 400,929

8 Claims. (Cl. 4-101) The primary object of the present invention is to provide a novel and efiective urinal unit for automatically effecting a urinal flushing operation at intervals dependent on the extent of use of the unit. I v

The invention was primarily devised for use in a unit comprising a plurality of urinals enclosed in a lavatory or toilet room having an entrance doorway and a door movable to open and close the doorway and biased for movement into its doorway closing position by spring hinges or other suitable means. In the use of the present invention, each flushing operation is initiated whenever the lavatory door is opened during a period in which the urinals are not being flushed.

Another major object of the invention is to provide a simple and effective electrical control system for energizing and deenergizing a timing motor and for opening and closing valves and switches at suitable stages in the initiation and completion of each flushing cycle.

Another major object of the invention is to provide simple and effective means bywhich the opening of the lavoratory door may initiate the flushing of a plurality of urinals in the lavatory at automatically determined intervals.

More specific objects of the invention are to combine an individual flush valve. with each of the urinals in the lavatory for use in automatically passing a predetermined volume of flushing water into each urinal during each flushing cycle, and for initiating each such cycle by the actuation of a push button switch efiected by an opening movement of the lavatory door.

Another specific object of the invention is to provide a urinal unit with flush valves which can be easily modified to adapt them either for automatic operation or for manual operation.

Another specific object of the invention is to provide simple and effective means for varying the duration of each flushing operation.

Another important object of the invention is to provide modified apparatus which does not include a separate 'flush valve for each unit, but whichis operative to simultaneously flush each of a plurality of associatedurinals .at automatically determined intervals which may be'exactly like the flushing intervals occurring as above-described when separate flush valves aretassociated with the ditierent urinals.

The various features of novelty which characterize my annexed to and forming a part of this specification.

Of the drawings:

Fig. l is a diagrammatic illustration of a urinal flush valve unit or system;

Fig. 2 is an enlarged sectional elevation'of flush valves shown in Fig. 1; 1

one of the spring hinges d.

ice

Fig. 2a illustrates the flush valve shown in Fig. 2 modi fied for manual control;

Fig. 2b is an enlarged view partially in section of the flush valve shown in Fig. 2;

Fig. 3 is an enlarged sectional elevation of a solenoid valve shown in Fig. 1;

Fig. 4 circuit diagram schematically illustrating the operation of the apparatus shown in Figs. 1 and 3;

Fig. 5 is an end elevation of a horizontally disposed motor supporting means and associated mechanism;

Fig. 6 is a side elevation of apparatus shown in Fig. 5; and

Fig. 7 illustrates a modification of the flushing apparatus collectively shown in Figs. 1 to 6; and

Fig. 8 illustrates another modification of the apparatus collectively shown in Figs. 1 to 6.

The embodiment of the present invention illustrated by way of example in Figs. 1 to 6, comprises a plurality of urinals A installed in a lavatory or toilet chamber B which may be entered from time to time by a user or users through a doorway C normally closed by a door D. The door D is biased to its closed position, as by means of A self-closing switch E, which may well be of the push button type, is mounted in the door frame surrounding the doorway C, and so arranged that the switch will close when the door is opened and will be opened when the door is returned to its closed position, The closure of the switch E operates through electric control mechanism shown diagrammatically in Fig. 4, to open flush valves F separately associated with the different urinals A and thereby initiate urinal flushing operations.

As shown in Figs. 3 and 4, by way of example, the control mechanism includes an electric relay switch mechanism G, a synchronous motor H, a cam I, a cam switch mechanism J, and a solenoid coil K with an energizing coil k. In Fig. l, the elements G, H, I, I and K and associated control means are all included in a box or compartment L. The latter may,-and ordinarily will be, a

commercially available medicine cabinet, or analogous device imbedded in or otherwise attached to a side wall of the lavatory.

The control mechanism shown in Figs. 4, S and 6 includes conductor terminals 1, 2, 3, 4, 5 and 6. Energizing conductors Li and L2 connected to the terminalsl and 2, supply alternating current of conventional voltage and frequency, ordinarily. ll0 115 volts and 60 cycles per minute, respectively. The terminals 3 and 4 are connected by the energizing coil k of the solenoid valve unit K. The terminals of the switch E are connected between. the terminalsS and 6. lnFig. 4, the apparatus is shown in its stationary condition in which the switch E is open, the motor H is de-energized and stationary, and the cam I is in the position into which it moves at the end of each operating cycle. operative condition shown in Fig. 4, the closure of the switch E, effected when the lavatory door D is opened, starts the motor H into operation and thereby initiates an operation cycle which causes the cam I to rotate through an angle of 360 r The initial effect of the closure of the the opening of a pair-of contactors 30 whichare closejdf' when the coil is not energized, and thereby closes a second circuit between the terminals 1 and'Z. Said first circuit" With the control apparatus in the nonswitch E is to; close a first circuit between the supplyconductors L1 and; L2, which can be traced from the terminal 1 to theier:

met

3 isjyfiflb'the second:circuitis not, interrupted when the closure .ofthe-door Dopensthe switchli.

Said second circuit can be traced from the terminal 1 to the terminal 2 through the conductor 13, earn switch terminal 114; switch. blade 15, cam; switch. terminal 16, conductor 17, relay terminal 18, contactor 11, conductor 19, contactor 12, motor winding terminal 21, motor winding terminal 22 and conductor 19. Some of the current-passingfrom the conductor 17 to the conductor 19 passes from the latter to the conductor 9 and through the latter to the conductor 10. The closure of said sec- 0nd circuitwhich. sets the motor into rotation, also maintains a current flow through a shunt to the motor winding Said: shunt includes a portion of the conductor 19.- and the relayenergizing winding 9.

The rotation of the motor H rotates the cam I through suitable. connecting gears 23 and 24. The motor H may well be, and is assumed tobe, a synchronous motor making: oneyrotation per minute. The desirable rotation period of the cam I for each flushing operation, may vary with conditions of operation and may be adjusted by varying the; ratio of the gears 23 and 24. In the particular construction shown in Fig. 4, the gears 23 and 24 are so relatively proportioned as to rotate the cam I through an angle of 360, or a little less, in 165 seconds.

As shown in Fig. 4, the cam I is formed with a peripheral notchi, and the cam switch member j is a roller or-wheel which moves into and then out of the notch i as: the latter is moved past the wheel j. As shown, the cam switch I is of the type known as a microswitch, and the wheel 1' is connected by a pivot or axle j to one end of a resilient arm 25 having its other end anchored tothe body portion of the switch I. The arm 25 biases the-wheel j for movement into the notch i when the angularposition of the cam I permits. The previously mentioned switch blade formsa part or" the microswitclr I, and is connected to the arm by a link 26. When the wheel j moves down into the notch, the end of the-switch blade 15 previously engaging the terminal 16, is'rnoved into engagement with another terminal 27 of the switch I. The terminal 27 is connected by a conducto'r 28 to the relay switch terminal. This de-energiZes; the motor but not until the rotation of the cam I has moved the wheel-j out of the notch far enough to move the switch blade 15 back into engagement with the terminal 16'.

The movement of the switch blade 15 out of engagement with the terminal 16 and into engagement with the terminal 27, opens the previouslyestablished circuit including theconductor 13, switch blade 15 and conductor 17, but results in the energization of a third circuit which energizes the coil k of the solenoid valve K andth'ereby-maintains the energization of the motor H. The third'ci'rcuitmay be tracedfrom the terminal 1 to the terminal 2 through conductor 13, terminal 14, switch blade 15, terminal 27, conductor 28, conductor 29, terminal 3, solenoid winding coil k, terminal 4 and bridging conductor 7a. The voltage drop in the coil k results in a' p'ot'ential diiie'rence between the terminals 9a and 20, and thereby between the motor winding terminals 21, and 22, which is suilicient to maintain the motor in rotation so long as the switch blade 15 remains in engagement with the terminal 27. With the roller j biased for movement toward the cam wheel axis,- the blade 15 will remainyinfengagement with the terminal 27 throughout substantiallyithe entire period'in which the-roller is in contact with the wall of the notch i.

In practice, the period during which the wheel j is in thenotch i and the energization of the solenoidvalve K is.;m3intained, may.- well be about 7 seconds. As the wheel] moves out of the notch .i the-.energization of the solenoid valve-is interrupted, as is; the; energizationofi the A hereinafter xplained in: more det il on lgiz'ationof th e,. 'so1erioi,d, valve. res lts-in. th pass salient; flushing water. thro gh, the flu h valv s. F to fine.

Cit

urinals A, and the d'e-energization of the solenoid valve does not end. the.fiushing operation immediately.. lnprao.

tice, the flushing operation ordinarily includes a period of about 7 seconds in which the solenoid pilot valve is wide open, and a further period of about 8-13 seconds during which the pilot valve is gradually closing but permits the flushing operation to continue. During each flushing operation the water used in flushing. each urinal may well be about threetquarts;

In the form of the invention shown in Fig. 1, the energizst-ii'm of the solenoid valve initiates a urinal flushing operation by automatically opening the flush valves F. One of the flush valves F of Fig. 1 is shown in section in Fig; 2 as comprising; a casing 31- enclosing a vertical piston chamber 32. The casing 31 is formed with a lateral water inlet passage 33 and a vertical outlet or discharge passage 34 below and extending downwardly away from the piston chamber 32. A normally closed outlet pipe 35 opens into the upper end of the chamber 32 throughthe upper end wall of the chamber. The lateral inlet 33- of each valve F is connected by an-individual branch pipe 36 to a water supply pipe 37. The latter isshown by dotted lines in Fig. 1, as in or back of the rearwallof the lavatory, and is connected to an unillustrated' source of water under a suitable lavatory pressure, which ordinarily is not less than 15 or 20 pounds per square inch. Each flush valve outlet passage 34 discharges through a pipe section 38 into the upper portion of the corresponding urinal A to flush and clean the latter.-

More or less of the body portion of a vertically movable piston- 39 extends upward into the chamber 32 through the open lower end of the latter. The body portion of the piston 39 is shaped and proportioned to have a slidingt in the chamber 32. The lowerend portion 40 of the piston 39 is of reduced cross section and extends into and closes the upper end of the outlet passage 34 except during the flushing operations. Eachfiushing operation is initiated by an upward movement of the piston 39 which opens the passage 34 and permits water to pass freely from the inlet passage 33 into the outlet passage 34.

Atthe end of'each flushing operation, the piston 39 moves downward, into the position in which its portion 49" closes communication between the inlet and outlet pas sages 3'3 and 34, respectively. The up and down movements of the piston 39, which initiate and terminate flushing operations, result from decreases and increases in the pressure in the portion of the piston chamber 32 above thejpiston 39. The piston 39 is formed with a restricted leakage passage or duct 41 through which water may pass from the inlet passage 33 into the portion of the chamber 32'fabove the piston. As shown in Fig. 2b, the leakage passage comprises an annular passage 42 surrounding the axisof the piston, a port or ports 41 through which the inlet passage 33 is in communication with the channel" 42), and; a restricted portor passage 43 extend in'g upward from the channel; 42 to the topof the piston ha er. .21-

The automatic flush valve F shown by way of example in Fig. 2, is similar to the manually controlled, com mercial type of flush valve shown in the Binnall Reissue Patent 20,246, dated January 19, 1937, except in respect to the means for initiating flushing operations. In the orm t he nv nt n o e tively llus a in F ss- 1 andl ach. bf j' he ndiv du o le pin s. '5. n ed:

to the upper'ends of the dififerent urinals A, is a branch of a controlfpipe 44 connected to the inlet of the normally closed valve element Ka ofthe solenoid valve K through a screen andjdrainelement 45 and a needle valve 46. The valve element Ka when open, passes water receiyed. through the needlevalve 46, to a waste or drain pipe 47'. The construction and operation of the solenoid v lve nitK- s ta ly-desc bed her aft n It may be practically convenientand, desirable in some:

mam I cases to include in the apparatus shown in Fig. l, flush valves F each having a piston 39 of the type and form used in the commercial, manually controlled, Binnall patent flush valve, and such a piston is shown in Fig. 2b. Furthermore, it may be desirable in some cases to employ a flush valve which may be operated manually or automatically, and in Fig. 2a I illustrate means by which the flush valve shown in Fig. 2 may be manually operated.

The piston 39 shown in Figs. 2 and 2b is formed with a normally closed central passage 50 which is large enough to rapidly discharge the water in the piston chamber above the valve when the central passage is opened. The latter is normally closed by a circular valve member 51 resting on an annular valve seat 52 surrounding the central passage 50. The valve member 51 is normally pressed against its seat by a spring member 53 comprising a central portion engaging the upper side of the valve 51, and having diametrically opposed end extensions with inturned end members 54 which extend into and are anchored in diametrically opposed portions of the piston 39. The valve member 51 has a central tubular extension 55 which extends downwardly from the level of the valve seat and as shown, has a telescopic extension 55a. The stem extension 5511 is readily removable and may well be removed when the fiush valve is automatically controlled in regular operation. It is shown in Figs. 2 and 2a.

In Fig. 2a a lever 56 is provided for manually opening the flush valve. The lever 56 extends through the central opening in an annular end portion of a cap 57 closing an aperture 58 in the flush valve casing. The lever 56 is formed intermediate its ends with a flange 59 which normally engages the inner side of said annular end portion of the cap member 57. When lateral pressure is applied to the outer end of the lever 56, the flange 59 is tilted and the inner end portion of the lever engages the lower end of the stem extension 55a and thereby tilts the valve member 51 and opens the central passage 56. This results in the almost instantaneous discharge through the central passage 50 of the water previously filling the portion of the piston chamber 32 above the piston 39. As the water passes out-of the upper end of the piston chamber through the passage 50, the pressure of the water in the supply passage 33 moves the piston upward into the position in which the bowed central portion of the spring 53 engages the upper end wall of the valve casing.

While the closure of the switch E immediately starts the motor H into rotation, the resultant flushing operation is not initiated until the cam I has nearly completed its revolution and the solenoid valve unit K has been energized. The unit K includes a valve body or casing element Ka formed with aligned inlet and outlet passages 60 and 61, respectively, and with a transversely extending passage 62. The latter when opened passes water from the inlet passage 60 to the outlet passage 61. The passage 62 is opened to initiate, and is closed to terminate each flushing operation. The passage 62 is opened and closed by a valve disc 63 which forms an end portion of a piston 64. The latter is mounted in a chamber 65 formed in the valve body Ka for movement of the piston 64 in the axial direction of the passage 62 toward and away from the position in which it closes that passage. The outer end of the chamber 65 is closed by a cap member 66. The latter includes an elongated tubular extension or sleeve 67 coaxial with the chamber 65 and port 62, and is open at its inner end. The piston 64 is formed with a central passage 68 coaxial with the port 62 and surrounded at the upper end of the piston by a. valve seat engaged by a valve member 69 which closes the passage 68 during non-flushing periods. The valve member 69 has an elongated stem 76 surrounded by an elongated sleeve 71. The latter is formed of magnetic material, which in the form shown, is loosely received in the bore of the extension 67. The piston 64 is formed 6 with a restricted charging duct '12 connecting the chamber space into which the inlet opens to the portion of the chamber above the piston 64. A bias spring 73 is interposed between the outer end of the piston 64 and the cap or end member 66 and tends to hold the piston in the position in which it closes communication between the inlet space 60 and the outlet chamber 61. The tubular extension 67 is surrounded by the coil k having its terminals connected to the control instrument terminals 3 and 4, as is shown diagrammatically in Fig. 4. The coil k is surrounded by a coil cover tube 74 which is clamped between the member 66 and an end casing member 75 a nipple 77 through which the solenoid valve unit K is connected to its housing structure L.

In the normal non-flushing condition of the apparatus including the flush valves F and their branch pipes 35,-

the passage 62 is closed and the water pressure in the supply pipe 37 is transmitted through the flush valves, their branch pipes 35, to the pipe 44, and thence through connections 45 and 46 to the inlet chamber 60 of the valve member K. The pressure in the chamber 60 is transmitted by the duct 65 to the portion of the piston chamber 65 above the piston 64 and to the unoccupied space within the tubular extension 67. When the coil k is energized, the valve member 69 is raised and the water above the piston is immediately discharged to waste through port 62, outlet passage 61 and drain pipe 47. The resultant reduction in the pressure above the piston 64 causes the latter to move away from the port 62, and thereby initiate a flushing operation.

The flow of water through the pipe 44 from the branch pipes 35 is reduced to a trickle as soon as the flush valve pistons 39 move into their upper positions. In consequence, the amount of water passing away from the valve element Ka through the drain pipe 47 in the course of each flushing operation is quite small. The rate at which water passes from the pipe 44 into the valve element member Ka is regulated by adjustment of the needle valve 46. The screen and drain element 45 may readily be opened from time to time to eliminate fibers, sand, etc., which passes into the member 45 through the pipe 44, and is arrested by the screen in said member.

Desirable means for supporting the motor H and cam I, and a modified form of said cam, are shown in Figs. 5 and 6. As shown in those figures, the relay switch mechanism G, motor H, cam I and cam switch mechanism J are all mountedon a supporting member 86*.

The latter comprises a flat horizontal central portion with flanges 86a and 80b extending up and down, respec tively, away from the opposite side edges of said central portion. The flange 80a is screw connected to the back wall of the housing L as shown in Fig. 8, with the motor H above and the elements (3,1 and I below the central horizontal portion of the supporting elements 80.

The cam disc 1a differs fromthe cam I shown in Fig.4 in having a peripheral notch in which is of greater angular extent than the notch i of Fig. 4. In addition, a sector 81. is mounted on the cam disc Ia for angular adjustment about a hub portion 82, and is formed with an elongated slot 83 extending circularly about the axis of the hub 82. Clamping screws 84 extend through the slot 83 into the cam disc la. The sector'81 has a leading peripheral'edge portion flush with'theunnotched peripheral edge portion of the disc Ia, and has a trailing peripheral edge portion 85 with a radius shorter than that of the unnotched portion of the disc Ia, and an intermediate peripheral edge portion 86 connecting said leading and trailing edge portions of the sector 81. As will be apparent, when the clamping screws 84 are loosened, the sector 81 may be adjusted angularly about the hub 82 relative to the cam disc la. The angular adjustment of the sector 81 relative to the cam disc Ia, varies the efiective angular extent of 6 thenotch ia andtherebymakes possible a variation in the length of; the period in which the'solenoid valve coil k is energized. during each revolution of the cam.

The previously described use. ofltlielavatory door D to initiate-a flushing operation. is practically simple and efiective, but other means may beuscdto accomplish the same general purpose. Two such other means are shown in Figs. 7 and 3, respectively. In. the arrangement shown in Fig. 7, a so-called electric eye is used. to initiate a flushing action. As diagrammatically shown in Fig. 7, the electric eye comprises a light source 87 transmitting light to a photocell, the output circuit of which is connected to the input circuit of an electronic amplifier and relay. 89. The output terminals 89a'of the relay 89- are. adapted for connection to the terminals d and 6: shown in Fig. 421s those terminals are connected by the closure of the switch E of Fig. 4.

In the forms of the invention shown in Fig. l and in Fig. 7, there is art-individual flush valve F associated with each urinal A. In the modification illustrated in Fig. 8, separate flushvalves F for thedifierenturiuals arenot used, but the control action collectively effected by the flush valves F the solenoid valve .unit K in the arrange-. ments previously described is eiiectcd by a solenoid valve unit KB.

in the modification shown in Fig. 8, the flush valves F are operatively replaced by the solenoid valve unit KB. The latter may cc identical in structure and generalmode of operation to the previously described solenoid valveunit K, but has a substantially greater water flow capacity. The unit KB includes a valve element Kb which may be identical with the valve elementlia shown in Fig. 3 except for the larger dimensions ofthe element Kb. The inlet chamber tit of the element Kb is supplied. with flushing water at properpressure by a supply pipe 9.0. Thelatter isconnected to theinletoli through ashut-ofi valve 91 and a strainer 92,. The outlet chamber 61 of Fig. 8 is connected to an outlet pipe 93 which supplies flushing Water to a manifold 94. The latter as shown, supplies Water to six pipes 95 each adapted to'passifiushing'water directly to'a corresponding urinal A. Each pipe 95 is connected tothe manifold through an element 96. Each element 96 includes a-throttling valve 97 which may be adjusted, as by means of a screw driver, to regulate the volume of water passing from the manifold 94 to the corresponding urinal.

As will be readily apparent, the apparatus may be modified to provide for more than one flushing operation during each rotation of cam i or cam In. if either camis formed with aplurality of notches! or in, respectively, at suitable intervals along the peripheryof'the cam, the apparatus w ll be operative to effect a separate flushing operation for each notch in the cam.

While in accordance with the provisions of the statutes, 1 have illustrated and described the best forms of embodiment of my invention now known to me, it will be apparent to those skilled in the art that changes may be made in thctorms of the apparatusdisclose'dwithout departing from'the spirit of my invcnti'on'as set fo'rth'in the appended claims and that in some cases "certain features of'my invention may be used 'to advantage without a corresponding use of other features.

Having now described my invention, what I claim as 1 new and. ,desireto secure .by Letters Patent, is:

l. A waste receivingunit. comprisingat' least one. urinaL.

mechanism for flushing the urinal comprising a valve controlling the supply of flushing liquid to the urinal and means including a timing means initiating and terminat ing each flushing operation of'said valve at a predeter' mined interval following the initiation of the operation of said timing means, and actuating means'initiating each cycle of operation of said timing means, said timing means stopping its cycle after the completion of each flushing operation regardless of intermediate operation of said actuating means during such predetermined interval.

2. A urinal flushing unit as specified in claim 1, comprising a plurality of urinals and a separate flush valve supplying flushing water to each urinal, and means actuated by said timing means for initiating the discharge of water of each flush valve at the beginning of each flushing, operation.

3. A urinal flushing unit as specified'in claim 1, comprising a single flush valve passing. flushing water to each of said urinals.

4. A urinalfiushing unit as .spccifiedin claim 1, including separate means for adjusting the rate at which flushing water is supplied to each urinal.

5. A urinal flushing unit as specified in claim 1, in which the actuating means comprises a photocell,.a source of light normally transmitted to said photocell and arranged to be intercepted by a user, and amplifying and relaying. means connected to said photocell and actuated to initiate a flushing operation when the transmission of light to the photocell is interrupted.

6. A waste receiving unit comprising at least one urinal, mechanism for flushing the urinal, comprising a valve controlling the supply of flushing liquid to the urinal and means including a timing means initiating and terminating each flushing operation of said valve at a predetermined interval iollowin the initiation of the'operation of said timing means, and actuating means initiating each cycle of operation of said timing means, said timing means stopping the cycle after the completion of each flushing operation regardless of intermediate operation ofsaid actuating means during such predetermined interval, saidtiming means comprising a motor and a cam connected to said motor to rotate when said motor rotates, acontrol element initiating and terminatingthe fiushing.operation-,- means carried by said cam for actuating 'said control element in one direction and then in'the opposite direction as said camis successively-moved in the-first and second angular positions.

7. Urinal flushing apparatus as specified in claim 6, including means for varying the time required to move the cam between its first and second positions.

8. Urinal flushing apparatus as specified in'claim' 7 including means for varying the angular'distance between said first and second cam positions.

ReferencesCited in the file-of this patent UNITED STATES PATENTS 644,488 Adams .Feb.-27,.19(:lO 1,029,281 Davis Ju'riejl1,-1912 1,366,761 Adell Jan. 2 5, 1921 1,639,679 Zsoldos Aug..23, 1927 1 2,395,150 Sloan et al Feb. 19, 1946 2,507,966 Filliung May 16, 1950 2,603,794 Bokser July 22, 1952 2,635,691 Filliung Apr. 21, 1953. 2,688,141 Pilliung Sept. 7, .1954

Images