US2949214A - Pumps - Google Patents

Description

S. H. DAVEY Aug. 16, 1960 PUMPS Filed May 1o. 195e 5 Sheets-Sheet l' INVENTOR SAMUEL H.DAv|=.Y

Q4/M Mazhd w *TToRNEYs Aug- 16, 1960 s. H. DAVEY 2,949,214

PUMPS Filed May 1o. 1956 s 'sheets-sheet 2 mvENToP. SAMUEL H DAvEY @WM M Mw www ATTORNEYS S. H. DAVEY Aug. 16, 1960 PUMPS 3 Sheets-Sheet 3 Filed May l0. 1956 mve uToR AnuEl. H. .DAVEY United States "iatent Q PUMPS Samuel Howard Davey, Bramer-ton St., London, England Filed May 10, 1956, Sel'. N0. 584,137

Claims priority, yapplication Great Britain May 12, y1955 12 Claims. (Cl. 222-381) The invention relates to pumps and it is an object of the invention to provide an improved pump for pumping viscous liquids and the like (e.g. soap compound in gel form), which are hereinafter referred to as viscous iluids.

The invention provides a pump comprising two tubes having adjacent ends in overlapping telescopic relationship, the other end of one of the tubes being provided with an outlet valve permitting flow out of the interior of the tubes, but preventing or restricting ow into their interior through that end, the said one of the tubes being axially reciprocable so as to increase and decrease alternately the volume of the interior of the two tubes, and the other of the said two tubes being caused to move axially by the reciprocations of the said one of the tubes in such a way as to move the other end of the said other tube into and out of engagement with a stationary closure member whereby the said other end ofV they said other tube is alternately opened and closed on reciprocation of the said one tube.

Preferably the overlapping portions of the tubes are separated by a layer or lm of viscous uid, the arrangement being such that the layer of Huid provides by its viscosity a coupling between the said two tubes so that the said other tube is caused to move axially by the reciprocation of the said one tube as aforesaid. The said layer or iilin of viscous iluid may be provided by a fluid being pumped by the pump. The said other member may be biassed (eg. by its own Weight) to a position in which the said other end of that tube is in engagement with the stationary closure member. The said one tube may be bassed (c g. by a compressing spring) towards its position when the said interior volume is a maximum.

A specific construction of a soap dispenser for use by industrial operatives (e.g. in factories or foundries) in washing their hands and embodying a pump in accordance with the invention, will now be described by way of example with reference to the accompanying drawings in which:

Figure l is a perspective view of the soap dispenser showing a hand inserted into it,

Figure 2 is a similar view to Figure 1 witha portion of the casing broken away to expose the pump,

Figure 3 is an elevation of the pump detached from the casing and showing the soap trough in its fully depressed position and the shorter cylinder in its lower position,

Figure 4 is a view similar to Figure 3 but showing the soap trough in an intermediate position and showing the shorter cylinder in its raised position,

Figure 5 is a rear elevation of the soap dispenser,

Figure 6 is a sectional View on the line 6-6 of Figure 5,

Figure 7 is a fragmentary perspective view of theback plate of the dispenser, showing one of the fixing eye bolts,

Figure 8 is a perspective view of the rear of the cover plate, and

Figure 9 is a perspective view of the disfcv outlet valve and` its mounting.

In this example the casing 21 of the soapy dispenser t '2,949,214 Patented Aug. 16,v 1960 ICC centrally at one end isbent at two positions intermediate Y in its width sov as to provide the side and front walls 23, 24 respectively of the casing 21. The cut-out is shaped sothat the lower edge 25 is straight and the sid-e edges 26 curve arcuately upwards. Thesheet is bent so that the sides 23 ofthe casing` 21 extend in directions perpendicular to that of the front wall 24, and so that the portions of the sheet intermediate the side and front walls 23, 24 curve smoothly so as to provide a pleasing appearance. When the sheet isV bent, vas aforesaid, the cutout provides an access opening 27 into the interior of the casing 21 which is generally rectangular in shape. The curved upper marginal edge portions 31 of the side walls 23 of the casing 21 are bent inwardly so that the said curved intermediate portions between the side and front walls 23, 24 of the casing are continued smoothly over the arcuate portion 31. An arcuate plate 32 is secured to the under surface of each inwardly bent arcuate portion 31 of the side walls 23 respectively,- so that a lengthwise extending strip of each arcuate' plate 32 extends laterally into the top opening 27. The lower horizontal edge 25 of the top opening 27 is bent over to form a downwardly inclined, inwardly directed ange 33 (see Figure 6) to engage with a channel 34 on the cover plate 22; The base of the casing 21 is formed by a rectangular plate, the front and side marginal edges of that plate being smoothly upturned and are welded to the side and front walls 23, 24 of the casing 22.

The back 35 of the casing is formed from a rectangular sheet of met-al, the side and lowermarginal edges of theA sheet being upturned to form flanges 36. The upper marginal edge of the sheet is bent so as to provide a U-shaped groove 3'7, the open side of the groove lying in the'planeV of the sheet 35 and the depth of the groove 37 extending in the reversev direction to that of the side andk base flanges 36. The back sheet 35 is welded to the casing21 so that the freeedges of the anges 36' are level with the rear edges of the sides 23 and base'of the casing 21 and the plane of the sheet 35 Vis off-set inwardly from the plane of those edges thereby forming a rectanglar., vertically extending recess.

An upwardly directed, U-shaped channel 41 is secured to the back of the casing by means of two L-shaped brackets 42 so that one side vertical, wall 43 of the channel 4l is received within the U-shaped groove 37 of the back sheet 35. and is in contact therewith. The upper marginal edges 44 of the side walls ofthe channel are inturned to form, respectively, inwardly directed anges. Two similar U-shaped, elongated catch members 45 are slidably located within the U-shaped channel 41 and are inter-connected by a helical tension spring 46 so that they are urged thereby into contacting positions. The open side of each catch member is bridged by a short' cross-piece 47 adjacent the outside end thereof.

A lock 51 is secured to the external surface of the back plate 3S of the casing 21 adjacent the base. Akey hole 52 is formed in the base of the casing, which key hole 52 is of similar shape and is aligned with, a key hole in the lower wall ofthe housing of the lock 51'. A vertical metal strip 53 is slidably secured centrally to the back plate 35 of the casing 21 by meansof two spaced saddles 5-4, and carries a short cross-piece 55 at its lower end. The upper edge ofthe vertical strip 53 is' cut-away to `form an arrow-shaped end 56 and the strip 53 is movable from a position in which the point ofthe arrow-shaped end 56 just projects through anaperture in the base of the U-shaped channel 41 and the cross-` piece 55 rests adjacent the upper wall of the housing of the lock 51, to a second position in which the strip 53 projects through the aperture in the base of the channel into the channel so as to force the catch members 45 apart against the urge of the helical spring 46. The lock 51, vertical strap 53, and the U-shaped channel 41 are all contained in the said vertically extending recess formed at the back of the casing 21. K

The cover plate 22 is arcuate in shape, as aforesaid, and is provided with a row of four holes 57 through which the four iingers of a hand (shown in chain lines in Figure l) may be inserted respectively, into the casing 21. Each hole 57 is cylindrical in shape and is defined by a short metal tube 58 secured to the underside of the cover plate 22. The lower edge of the cover plate 22 is bent to form the hook-like channel 34, the open side lof the channel 34 being outwardly directed. Two arcuate, L- sectional metal strips 61 are secured to the under-side of the cover plate 22 adjacent the side edges respectively. A metal strip is bent intermediate in its length to form a generally V-sectioned channel 62. One arm 63 of the channel is dat and the other arm 64 is arcuate in section. The llat arm 63 is secured to the undersurface of the cover plate 22 adjacent the upper edge thereof. The central portion 65 and both end portions 66 of the arcuate arm 64 are cut-away, the end portions 66 being cut-away so that the outside edges 68 of the remaining two lug-like portions 67 are both inclined downwardly away from the centre. A small rectangular shaped cutout is formed at'the outside edge of each of the remaining portions 67 adjacent the base thereof, to provide an undercut groove 69.

The cover 22 is secured to the remainder of the casing 21 by engaging the hook-like channel 34 at the lower edge of the cover plate 22 with the inwardly directed ilange 33 at the lower edge of the top access opening 27. The cover 22 is then moved in an arcuate path about that engagement so that the inclined edges 68 of the two lug-like remaining portions 67 of the metal strip secured to the upper edge of the cover 22 engage the cross-pieces 44 bridging the open side of the catch members 45. On further movement of the cover 22 the said inclined edges 68 act as cams and force the two catch members 45 outwardly apart until the cross-pieces 47 pass beyond the inclined edges 68 and engage respectively with the under-cut grooves 69.

Mounted within the casing 21 is a pump 71 which normally maintains a substantially rectangular opentopped tray 72 full of a soap compound in gel form.

The pump 71 comprises two steel tubes 73, 74, the tube 73 being about 8% inches long by about 1% inches external diameter and the tube 74 being about 35/3 inches long by about 11A inches internal diameter, the difference `between the said two diameters being 0.012 inch. The tubes 73, 74 are supported by three lugs 75 extending horizontally from a vertical steel strip 76, there being one lug at each end of the strip (the distance between those two end lugs being about 85/16 inches) and an intermediate lug spaced about 3% inches from the bottom lug. The top and intermediate lugs have circular apertures in them which provide bearings for the longer tube 73 to slide axially. A helical wire compression spring 77 surrounds the longer tube 73 between the top and intermediate lugs 75 and urges that tube 73 upwardly to a position in which about 1% inch of the upper tube 73 projects above the top lug 75. The upwardmovement of the longer tube 73 is limited by means of a ring 78 which surrounds it and abuts upwardly against the two ends of a pin 79 extending diametrically through the longer tube 73, the ring 78 having an annular cutout to receive the thickness of the ends of the pin. The ends of the spring 77 abut respectively against the ring 78 and the intermediate lug 75. The shorter tube 74, which constitutes a cylinder and a movable inlet valve member for the pump, overlaps the lower end of the longer tube 73 so that it is in telescopic relationship with it and is thereby maintained in position, the shorter tube 74 being axially movable through about 1A inch between the intermediate and bottom lugs 75.

The vertical strip 76 is supported by two strong horizontal steel strips 81 which are welded to it adjacent the top and intermediate lugs 75, which horizontal strips 81 carry `at their ends downwardly projecting members 82 which lit respectively within four eyes 83 outstanding from a vertical back plate 84 (see Figures 5 and 7) adapted to be secured to a wall by screws. The back sheet 35 of the casing 22 is received between the back plate 84 and the vertical pump supporting strips 76, 81 and is thereby secured in position, the back of the casing being formed with four apertures 85 through which the eyes 83 pass. Rubber sealing washers 86 are interposed between the back plate 84 and the back 35 of the casing 21,V around the respective eyes 83, so as to l form liquid-tight seals to the aforementioned four apertures.85 through which the eyes 83 pass. Spring wire members (not shown) project from vertically extending slots in the rear faces of the respective downwardly projecting members 82 which engage within the eyes 83, and those spring wire members serve to press the back 35 of the casing 22 against the sealing Washers 86.

The tray 72 is mounted within the casing 22 immediately below the finger holes 57. The tray 72 has centrally of its lower face 87 a downwardly extending stub tube 88 which ts closely within the top end of the longer tube 73 of the pump. 'Ihe tray 72 contains a horizontalV platform 89 (Figures 3 and 9) forming a false bottom, which platform 89 is provided with six short downwardly projecting strip legs 91 spaced outwardly away from the edge of the platform and which space the platform 89 upwardly away from the true bottom 92 of the tray 72 and also engage against the sides of the tray 72 to prevent horizontal movement of the platform 89, there being a clearance between the edges of the platform 89 and the sides of the tray 72. Beneath the platform 89 is supported a disc valve closure member 92 which is welded to the centre of a spring steel strip 93 extending along the central length of the underside of the platform 89, the end 94 of the spring strip being welded to the platform. The spring 93 is downwardly bowed in its centre, and its other end 9S l abuts against the underside of the platform 89 so that the disc 92 is resiliently urged against the top end of the stub tube 88 to close that tube and to constitute the outlet valve of the pump.

In use of the apparatus the part of the interior of the casing 22 beneath the tray 72 is substantially filled with the above-mentioned soap compound in gel form which in this example is of the kind known commercially under the trade name Ibex anti-dermatitis hand cleanser. The two tubes 73, 74 are normally full of the soap compound so that when fingers are passed into the casing 22 through the finger holes 57 and the tips of those fingers are pressed downwardly on the platform 89 in the trap 72, the longer tube 73 is thereby depressed against the action of its spring 77 until the bottom of that tube 73 meets the bottom lug 75 (see Figure 3). During that action soap compound from within the longer tube 73 is expelled past the disc outlet valve 92 into' the tray 72, and any excess over that required to maintain the tray 72 full overiiows from the tray 72 into the main bulk of soap compound in the lower part of the casing 22.

When the lingers are withdrawn the longer tube 73 is moved to its upper limit position by the spring 77. There is a film or layer of the soap co'mpound between the two tubes 73, 74 and consequently while the longer tube 73 is moving upwardly there is an upward force Y exerted on the shorter tube 74 due to the viscosity of the e it to engage the intermediate lug 75, the shorter tube 74 then being maintained in that raised position for the remainder of the upward movement of the longer tube 73 (see Figure 4). There is thus a gap 96 between the lower end of the shorter tube 74 and the bottom lug 75 which permits soap compoundy to `be drawn into' the shorter tube 74, to fill it, by the action of the upward movement of the longer tube 73,A the outlet valve being closed by the disc 92 during that movement` When the upward' movement of the lon'ger tube 73 ceases the shorter tube 74t descends under its own weight until its lower end meets the bottom lugY 75 (Figure l). It will thus be appreciated' that theshorter tube 74 acts asv the cylinder of the pump` and also, in conjunction with'` the bottom lug "75, acts as the' movable inlet valve irnember ofthe pump.

In this example the helical spring 77 has about 25 turns and its strength increases from about 3 pounds when the longer tube 73 is at its upper limit position toV about 31/2 pounds when the longer tube 73 is at its lower limit position.

I claim:

1, A reciprocating pump for pumping viscous fluids comprising a first tube, a second tube co-axial with said first tube and having an end portion in relatively closelyspaced overlapping telescopic relationship with an end portion of said rst tube, both of said tubes being axially reciprocable relative to each other, outlet valve means at the end of said first tube remote from said overlapping end portion to permit flow out of the interior of the tubes but to prevent flow in the reverse direction, inlet valve means at the end of the second tube remote from said overlapping portion to permit flow into the interior o'f the tubes but to prevent iiow in the reverse direction, said inlet valve means including a stationary closure mem ber against which the remote end of said second tube normally seats, and at least when the pump is in use, a layer or film of viscous fluid separating the overlapping portions of the two tubes and which, by its viscosity, provides a coupling between the tubes, whereby when said first tube is reciprocated towards the second tube the volume of the interior of the tubes is decreased, forcing fluid out o'f the outlet valve means, said second tube being seated against the closure member to close the inlet valve means, while when said first tubey is moved away from the second tube, the latter, dueto the fiuid coupling, temporarily moves with the first tube and away from the closure member to permit iiuid to iiow into the interior of the tubes.

2. A reciprocating pump according to claim l, wherein said second tube is biased by gravity.

3'. A reciprocating pump as claimed in claim 1, in which the said layer or filmA of viscous fluid is provided by the fiuid being pumped.

4. A reciprocating pump as claimed in claim 3, in which said second tube is biased to a position in which said remote end normally seats against the stationary closure member.

5. A reciprocating pump as claimed in claim 4, in which said second tube is biased by gravity.

6. A pump for pumping viscous fluid, comprising in combination a first tube, a second tube, said first and second tubes having adjacent ends in overlapping telescopic relationship to provide a straight flow path therethrough of substantially uniform diameter throughout its length, an outlet valve positioned at the other end of said first tube to permit flow out of the interior of the tubes, but preventing or restricting flow into their interior through that end, and valve means for opening and closing the other end of saidl second tube, said valve means comprising two mutually spaced opposed surfaces provided by the overlappi-ng portions of the inner and outer surfaces of two tubes, a stationary valve closure member below said other end of said second tube and with which the said other end'of the said second tube opposed surfaces, which layer extends throughoutv the entire length of the opposed surfaces and which, by its viscosity, provides a viscous coupling between the tubes,

said viscous coupling constituting the sole coupling between said tubes and being such that recipro'cation of the said first tube causes the said other end of the said second tube to move into`and out of engagement with the said closure member to open and close the said other end of the second tube.

7. A reciprocating '.pump for pumping viscous fiuids comprising a first tube, a-'second tube co-ax'ial with said first tube and having an end portion in relatively closely'- spaced overlapping telescopic relationship with an end portion of said first tube, both of said tubes being axially reciprocable relative to each other, outlet valve means l at the end of said first tube vremote from said overlapping end portion to permit flow out of the interior of the tubes, inlet valve means at the endv of the second tube remote from said overlapping portion to permit ow into the interior of the tubes, said inlet valve means including a stationary valve closure member adjacent the said remote end of the second tube, said second tube being normally biased to engage the remote end thereof with said stationary valve closure member, abutment means for limiting movement of the second tube away from the stationary valve closure member, and a layer of viscous fiuid separating the overlapping portions of the two tubes and which, by its viscosity, provides between the tubes a coupling which is only effective on relative reciprocable movement between the two tubes.

8. A pump for pumping viscous liquids comprising a container for the liquid, a vertical pump cylinder at least partially immersed in the liquid, said cylinder comprising an open ended tube of uniform internal cross-section through its entire length, a stationary valve closure member below said pump cylinder against which the lower end of said pump cylinder normally rests, thereby to close that end of the pump' cylinder, a piston cylinder co-axial with the pump cylinder and formed as a second open ended tube of uniform internal cross-section throughout its entire length and having its lower end portion loosely inter-fitting in sliding telescopic relationship with said pump cylinder to provide an open ended annular space between said overlapping portions of the cylinders, a layer or film of the liquid to' be pumped at least partly filling the said space between the overlapping portion of the cylinders, and which by its viscosity provides a viscous coupling between said two cylinders, guide means fixed to the container for guiding said piston cylinder for vertical reciprocal movement towards and away from said stationary valve closure member, an abutment fixed to the container, a spring acting between the abutment and said piston cylinder to bias said piston cylinder to its upper limit of movement, and an outlet valve positioned at the upper end of the piston cylinder permitting fiow out of the interior of the two cylinders through that end of the piston cylinder, Whereby on reciprocation of the piston cylinder movement of the said piston cylinder towards the valve closure member causes the volume of the interior of the cylinders to be decreased and fluid to be forced out past the outlet valve while movement o'f the said piston cylinder away from the valve closure member causes the pump cylinder to be temporarily moved away from the valve closure member due to the viscous coupling between the piston and pump cylinders thereby permitting huid to flow into the interior of the cylinders.

9. A reciprocating pump for pumping viscous fluids comprising a first tube, a second tube coaxial with said first tube and having an end portion in relatively closely spaced overlapping telescopic relationship with an end portion of said first tube, both of said tubes being axially reciprocable relative to each other, outlet valve means at the end of said first tube remote from said overlapping end portion to permit flow out of the interior of the tubes but to prevent ow in the reverse direction, said outlet valve means comprising a closure member normally biased into engagement with the remote end of said first tube and which is opened against its bias to permit flow of fluid out of the interior of the tubes, inlet valve means at the end of the second tube remote from said overlapping portion to permit flow into the interior of the tubes but to prevent flow in the reverse direction, said inlet valve means including stationary closure member against which the remote end of said second tube normally seats, and at least when the pump is in use, a layer or film of viscous fluid separating the overlapping portio'ns of the two tubes and which, by its viscosity, provides a coupling between the tubes, whereby when said first tube is reciprocated towards the second tube the volume of the interiorof the tubes is decreased, forcing fluid out of the outlet valve means, said second tube being seated against the closure member to close the inlet valve means, while when said first tube is moved away from the seco'nd tube, the latter, due to the fluid coupling, temporarily moves with the first tube and away from the closure member to permit fluid to flow into the interior of the tubes.

10. A pump for pumping viscous liquids comprising a container for the liquid, a vertical pump cylinder at least partially immersed in the liquid, said cylinder comprising an open-ended tube of uniform internal cross-section through its entire length, a stationary valve closure member below said pump cylinder against which the lower end of said pump cylinder normally rests, thereby to close that end of the pump cylinder, a piston cylinder coaxial with the pump cylinder and formed as a second openended tube of uniform internal cross-section throughout its entire length and having its lower end portion loosely inter-fitting in sliding telescopic relationship with said pump cylinder to provide an open-ended annular space between said overlapping portions of the cylinders, a layer or lm of the liquid to be pumped at least partly filling the said space between the overlapping portion of the cylinders, and which by its viscosity provides a viscous coupling between said two cylinders, guide means fixed to the container for guiding said piston cylinder for vertical reciprocal movement towards and away from said stationary valve closure member, an abutment xed to the container, a spring acting between said piston cylinder and said abutment to bias said piston cylinder to its upper limit of movement, an outlet valve positioned at the upper end of the piston cylinder permitting flow out of the interior of the two cylinders through that end of the piston cylinder, and abutment means for limiting. movement of the pump cylinder away from the valve closure member, whereby on reciprocation of the piston cylinder movement of the said piston cylinder towards the valve closure member causes the volume of the interior of the cylinders to be decreased and fluid to be forced out past the outlet valve while movement of the said piston cylinder away from the valve closure member causes the pump cylinder to be temporarily moved away from the valve closure member due to the viscous coupling between the piston and pump cylinders thereby permitting fluid to flow into the interior of the cylinders.

ll. A pump for pumping viscous liquids comprising a container for the liquid, a vertical pump cylinder at least partially immersed in the liquid, said cylinder comprising an open ended tube of uniform internal crosssection through its entire length, a stationary valve closure member below said pump cylinder against which the lower end of said pump cylinder normally rests, thereby to close that end of the pump cylinder, a piston cylinder coaxial with the pump cylinder and formed as a second open-ended tube of uniform internal crosssection throughout its entire length and having its lower end portion loosely intertting in sliding telescopic relationship with said pump cylinder to provide an open-ended annular space between said overlapping portions'of the cylinders, a layer or iilm of the liquid to be pumped at least partly filling the said space between the overlapping portion of the cylinders, and which by its viscosity provides a viscous coupling between said two cylinders, guide means fixed to the container for guiding said piston cylinder for vertical reciprocal movement towards and away from said stationary valve closure member, said guide means comprising a rigid vertical member and two vertically spaced arms carried by said member and having aligned guide passages through which the said piston cylinder fits for sliding movement, an abutment fixed to the container, a spring acting between said piston cylinder and said abutment to bias said piston cylinder to its upper limit of movement, an outlet valve positioned at the upper end of the piston cylinder permitting flow out of the interior of the two cylinders through that end of the piston cylinder, and abutment means constituted by the lower arm of said two vertically spaced arms for limiting movement of the pump cylinder away from the valve closure member, whereby on reciprocation of the piston cylinder movement of the said piston cylinder towards the valve closure member causes the volume of the interior of the cylinders to be decreased and uid to be forced out past the outlet valve while movement of the said piston cylinder away `from the valve closure member causes the pump cylinder to be temporarily moved away from the valve closure member due to the viscous coupling between the pistonV and pump cylinders thereby permitting fluid to ow into the interior of the cylinders.

12. A reciprocating pump for pumping viscous fluids comprising a rst tube of uniform external cross-section throughout its entire length, a second tube of uniform internal cross-section throughout its entire length coaxial with said rst tube and having an end portion in overlapping telescopic relationship with an end portion of said first tube, the external cross-section of said first tube being slightly smaller than the internal cross-section of said second tube so that the adjacent surfaces of the overlapping portions of the tubes are closely spaced, both of said tubes being axially reciprocable relative to each other, outlet valve means at the end of said first tube remote from said overlapping end portion to permit flow out of the interior of the tubes but to prevent flow in the reverse direction, inlet valve means at the end of the second tube remote from said overlapping portion to permit flow into the interior of the tubes but to prevent flow in the reverse direction, said inlet valve means including a stationary closure member against which the remote end of said second tube normally seats, and at least when the pump is in use, a layer or film of viscous fluid separating the overlapping portions of the two tubes and which, by its viscosity, provides a coupling between the tubes, whereby when said first tube is reciprocated towards the second tube the volume of the interior of the tubes is decreased, forcing fluid out of the outlet valve means, said second tube being seated against the closure member to close the inlet valve means, while when said first tube is moved away from the second tube, the latter, due to the fluid coupling, temporarily moves with the first tube and away from the closure member to permit uid to flow into the interior of the tubes.

References Cited in the file of this patent UNITED STATES PATENTS 179,096 Clark et al. June 27, 1876 642,119 Heysinger Jan. 30, 1900 1,805,790 Titus May 19, 1931 1,979,014 Schleif Oct. 30, 1934 2,000,493 Miller May 7, 1935 2,443,981 Funk et al. June 22, 1948 FOREIGN PATENTS 288,963 Great Britain Aug.'2, 1928

Images