US2756759A

US2756759A - Apparatus for cleaning vehicles

Info

Publication number: US2756759A
Application number: US384209A
Authority: US
Inventors: Swain Charles David
Original assignee: Daimler Hire Ltd
Current assignee: Daimler Hire Ltd
Priority date: 1952-10-24
Filing date: 1953-10-05
Publication date: 1956-07-31
Anticipated expiration: 1973-07-31

Description

July 31, 1956 c. D. swAlN 2,756,759

APPARATUS FOR CLEANING VEHICLES Filed oct. 5, 195s 4 sheets-sheer 1 July 31, 1956 c. D. swAlN 2,756,759

APPARATUS FOR CLEANING VEHICLES Filed oct. 5, 1955 4 sheets-sheet 2 July 3l, 1956 c. D. swAlN 2,756,759

APPARATUS FOR CLEANING VEHICLES J Filed Oct. 5, 1955 4 Sheets-Sheet 3 I/VVENTR s3 www, M/ M Walla-A,

HTTOR/VEVS July 3l, 1956 c. D. swAlN 2,756,759

APPARATUS FOR CLEANIYNG VEHICLES Filed oct. 5, 1953 4 sheets-sneer 4 fN VEA/TOR Y ai wlw, 4, @Mw ,2L/5,

nted States Patent Office p 2,756,759 Patented July 31, 1956 APPARATUS FOR CLEANING VEHICLES Charles David Swain, London, England, assignor to Daimler Hire Limited, London, England, a British company Application October 5, 1953, Serial No. 384,209

Claims priority, application lGreat Britain October 24, 1952 The invention relates to apparatus for cleaning vehicles and it is an object of the invention to provide improved apparatus for that purpose. v

The invention provides apparatus for cleaning vehicles, which apparatus comprises, in combination, a plurality of liquid outlets, means for supplying cleaning liquid to the liquid outlets, a carrier for supporting the liquid outlets so that during operation of the apparatus the liquid issues from the liquid outlets to impinge on the sides of a vehicle to be cleaned, a track above the level of the top of the vehicle, by which track the carrier is supported with the liquid outlets below the level ofthe track, and rnotor-operated ydriving means for moving the carrier along the track so that liquid issuing from the liquid outlets may be traversed along the length of the vehicle.

Freferably two sets of liquid outlets are lprovided and two separate means are provided for supplying different cleaning liquids to the two sets respectively. One .of the supply means preferably includes a reservoir for a detergent solution (e. g. a solution of soap or a soapless detergent) and a pump for pumping the detergent solution to the appropriate set oi liquid outlets. The other supply means is preferably connected to a pressure water supply to supply water to the other set of liquid outlets. Means are preferably provided for selectively rendering operative one or other of the supply means.

Means are preferably provided for automatically reversing the direction of movement of the carrier when it reaches a predetermined position on the track (e. g. one end thereof) and means are also preferably provided for stopping the movement of the carrier when it reaches another predetermined position on the track (e. g. the other end thereof).

Two specific constructions of apparatus embodying the invention will now be described by way of example and with reference to the accompanying drawings, vin which:

Figure l is a perspective View of one motor-car washing apparatus with a motor-car being washed indicated in chain lines,

Figure 2 is an enlarged side view of part of the apparatus shown in Figure l, showing the carrier and some associated parts,

Figure 3 is a View partly in section on the line 3--3 in Figure 2,

Figure 4 is a perspective view of another motor-car washing apparatus,

Figure 5 is an enlarged side View -of part of vthe apparatus shown in Figure 4, showing the carrier and some associated parts,

Figure 6 is a view partly in section on the line 6 6 in` Figure 5,

Figure 7 is a perspective view of one end of the apparatus shown in .Figure 4, showing one of the limit switches about to be actuated,

Figure 8 is an enlarged view of one of the adjustable water nozzles of the apparatus shown in Figure 4, and

Figure 9 is an electrical circuit diagram of the apparatus shown in Figure 4. l

In the apparatus shown in Figures v1 to 3 two horizontal parallel spaced track rails 1'1 are secured at one end to a garage Wall 12 and are suspended by members 13, 14 from the wall 12 and from girders (not shown) forming part of a garage roof. Immediately below the track rails 11 there is a carrier 17 comprising two longitudinal members 15 respectively parallel to, and directly underneath the two rails 11, and twotransverse members 16. The carrier is suspended from the rails 11v by means of four sets of wheels -or rollers 18 which run thereon. Each track rail 11 is of inverted channel section having inwardly directed flanges 19 at its mouth, o'n which flanges 19 the wheels or rollers 18 are supported.

A pipe 21 bent to the shape of substantially an inverted U is supported by the carrier 17 in a vertical plane, the cross-piece of the U-pipe 21 being attached at 22 to the underside of each of the longitudinal members 15 of the carrier, centrally of their lengths, so that the plane of the U-pipe is perpendicular to the length of the track. The ends of the U-pipe 21 are about one foot or two feet above the floor 23 of the garage, which is itted with gratings 24 leading to a drain. The U-pipe 21 is connected to a pipe-line 25 above the track, along which pipeline water may be fed under pressure, the connections being made by viiexible piping Ztl. The U- pipe 21 is provided with jet nozzles 26 spaced about eighteen inches apart alongits length so that they may direct jets of water, substantially in the plane of the U, at the sides androofof a motor car 27 positioned substantially centrally beneath the track with its length substantially parallel thereto. A shorter pipe 28 extends centrally across the lower side of the carrier 17 perpendicular to the cross-piece of the U-pipe 21 and extends beyond the longitudinal ends of the carrier to down-turned ends29, 31 which each carry a yjet nozzle 26. This shorter pipe 2S is in communication with the vU-pipe 21 at its intersection therewith and the jet nozzles 26 at its `ends are positioned so that they may direct jets 'of water against the front and rear of the motorcar when the carrier is at appropriate positions along the track.

,Rearwardly of thel U-pipe'll.v a detergent pipe 32 is suspended from the longitudinal .members 15 of the carrier by short verticalr rods 33. This detergent pipe 32 has a centre portion 34 in the shape substantially of va shallow inverted V in a substantially vertical plane and of length just 4greater than the width of .the carrier. At each end of the centre portion a straight side portion 35 extends outwardly at an angle of about 30 to 50 to the vertical. .From the apex of the centreportion a short rear portion 36 extendsv rearwardly and upwardly at a shallow angle. These centre, side and rear portions of the kdetergent .pipe are perforated, as at 36, at various intervals along their length to provide nozzles at positions such that a spray of detergent liquid may be directed towards 'the motor car. Detergent liquid maybe supplied to the detergent pipe 32 by a flexible connecting pipe 37 Awhich extends from the centre portion of the detergent 4pipe to a pipe line 38 above the track. This pipe line 38 is connected by piping 41 through an velectrically driven pump 39 to a tank 42 for containing a supply of the' detergent liquid, which "in this case is a soap solution.

The carrier 17 is arranged to be driven :along the track *by a driving chain 43 whichpasses over a )driving sprocket wheel 44, mounted on fa horizontal axis ycentrally above vthe vrear end of the-track, .and an idler sprocket Wheel 3 y 45 centrally above the other end of the track, the lower length of the chain being secured to the carrier 17 at 46 and tensioned by a spring. The upper length of the chain is supported, so as to prevent sagging, by an idler sprocket wheel 48 carried by the carrier 17 and supported at the appropriate height above it. The driving sprocket 44 is driven through reduction gearing from an electric motor 49 so that the carrier 17 may be moved along the track at about 30 or 40 feet per minute.

At the ends of the track there are provided

limit switches

51, 52 each operated by a bell-crank lever 53 rotatable in a vertical plane from a position in which one of its arms is directed vertically downwards to another position in which its other arm is so directed, the angle between the arms of each bell-crank being about 60 to 80, each limit switch having a snap action. The bell-crank levers 53 are operated by means of

arms

54, 55 which extend centrally and longitudinally from the two ends respectively of the carrier and each has a laterally projecting roller 56 which moves the appropriate bellcrank lever 53 when the carrier 17 reaches the limits of its travel. The limit switch 52 at the front end of the track is arranged to operate a delayed relay to reverse the driving motor 49 so that on reaching the front end of its travel the carrier automatically moves towards the rear end of the track after a short delay. The limit switch 51 at the rear end of the track is arranged to operate a relay to stop the driving motor 49.

The controls for the apparatus comprise a water-valve operating arm 57 having two positions R and S labelled rinse and soap respectively, a main electric switch 53, controlling the electricity supply, and three pushbutton switches, 61, 62, 63, controlling the driving motor,

and incidentally the detergent pump 39 when the valve arm is in the soap position, these three switches being labelled reverse, forward and stop respectively.

In the operation of the apparatus the valve arm 57 is then set to rinse, whereupon jets issue from the water nozzles 26, and the forward button 62 is pressed, whereupon the water jets are traversed along the whole length of the motor-car 27 so as to wet the motor-car thoroughly. When the carrier 17 reaches the end of its travel in that direction and operates the reversing limit switch 52 an electrical switch is thereby closed to light a green lamp 64 provided on the panel 65 on which the controls are mounted. On seeing this lamp 64 light the operator moves the valve arm 57 to its soap position. The water supply to the water nozzles 26 is thereby cut off and at the same time a switch 66 in the detergent pump motor energising circuit is closed by means of a link 67 connected to the valve arm 57. Consequently during the automatic return movement of. the carrier along the length of the track the spray of soap solution is traversed along the length of the motor-car. The spray is cut off automatically on operation of the limit switch 51 to stop the carrier 17 at the rear end of the track. The soap solution sprayed on to the car is lightly rubbed over it by means of a lambs wool glove or other suitable soft material so as to loosen dirt, or grease adhering to the motor car, and the valve arm 57 is then moved to its rinse position and the forward button 62 again pressed. The water jets 26 are thereby traversed along the length of the motor car and back again to rinse away the dirty soap solution. The valve arm 57 is then moved back to its soap position to cut off the water supply to the nozzles 26. f

The driving motor 49, and the soap spray if in operation, may be stopped at any time by pressing the stop button 63 and the carrier 17 may be restarted in the desired direction by pressing the forward or reverse button, 61 or 62.

The carrier may be alternatively caused to move along the length of its track and back again three timethe rst and third times with the water nozzles operating B1 to B6, C1 to C4 and D2.

and the second time with its detergent spray nozzles operating.

A hand gun 201 supplied by a flexible pipe 202 may be provided for directing by hand a jet of water against the underside of the wings and other parts of the motor car which are not reached by the jets from the nozzles 26.

In the apparatus illustrated in Figures 4-9, which is a modied form of that shown in Figures 1-3, a single rail track 111 is suspended from a garage or like roof by any of a number of lugs 101 and connected to a garage or like wall by means of a cross-member 102 and bracing members 103. A carrier 117 is suspended from the rail 111 by means of two sets of wheels or rollers which run on the inwardly directed flanges 19 of the rail 111.

A U-pipe 21 and a shorter pipe 28 for carrying water and a detergent pipe 32 and a rearward pipe 36 for carrying detergent are provided as in the apparatus shown in Figures 1-3. The nozzles 126 provided on the U-pipe 21 are mounted on swivelling elbows 104 so that the directions of the jets may be adjusted to suit any particular type of motor-car. Locking nuts 105 are provided to enable the elbows to be locked in any desired position.

The driving chain 43 passes over a front driving sprocket 44, driven by an electric motor 49, and over a rear idler sprocket 45, both of these sprockets being mounted below the track 111, as is the motor 49. One end of the chain 43 is secured to the carrier 117 at 106 and the other end is tensioned by a spring 47. The lower length of the chain runs on an idler pulley 148 mounted on the carrier 117.

Water is supplied to the U-pipe 21 by a pipe 107 and exible pipe 108 connected thereto. Detergent liquid is supplied to the detergent pipe 32 from the tank 42 through the pump 39 a pipe 109 and a flexible pipe 110 connected thereto. The

exible pipes

109 and 110 are supported intermediate in their length by a cradle member 171 mounted for pivotal movement about a horizontal pin 172 on a member 173 which is in turn mounted for pivotal movement about vertical pins 174 carried at the free end of an arm 175. The arm 175 is mounted for pivotal movement about a vertical axis at 176 on a support member 177 upstanding above the track 111. The members 171 and 173 together with the pivots 172 and 174 provide a universal jointed support for the

ilexible pipes

108 and 110. The arm 175 moves about its pivot as the carrier 117 runs along the track and the

llexible pipes

108 and 110 are thereby moved, and the arrangement at all times supports the lengths of those ilexible pipes intermediate their ends and prevents the flexible pipes from sagging unduly and so becoming entangled with themselves of getting in the way of the

pipes

21 and 32.

The front limit switch 52 is clamped to a T section girder 176 secured to the top of the track 111 and may be secured thereto by means of a bolt passing through any one of holes 177 at any one of a number of positions along the girder 176, depending upon which hole 177 is used, to provide any desired length of travel for the carrier 117.

The controls for the apparatus comprise a water valve 178 controlled by an operating arm 57, having a rinse position R and a soap position S. A motor start push-button switch 62 and an emergency stop pushbutton switch 63 the contacts of which lare normally closed. The arm 57 also controls a switch 66, the

vcontacts of which are closed when arm 57 is in the soap position and open when it is in the rinse position. A red lamp 64 is provided.

In a casing 179 there are accommodated four electromagnetic relays A, B, C, D having respectively operating coils A/S, B/6, C/4 and D/1 and contacts A1 to A5, The

phase windings

181, 182, 183 of 'the motor 49, and the

phase windings

191, 192, 193 of a motor 184 which drives the detergent pump 39, are connected through some of the relay contacts and the operating coils of overload protectors 185 having contacts 187 to a three phase L1, L2, L3 and neutral N main electric supply as shown in Figure 9, having a main switch 186.

In the operation of the apparatus the carrier 117 normally lies at the rear end of the track when a motorcar is driven into position beneath it, similarly to the position of the motor-car shown in Figure l. The main switch 186 is closed and then the motor start switch 62 is operated so as to close its contacts. The operating coil A/5 of the relay A is thereby energised through normally closed contacts B4, the

contacts

188, 189 of the forward limit switch 52, normally closed contacts 187 of the overload protector, and the emergency stop switch 63, from the lines L1 and N. The contacts A1, A2 and A3 thereupon close and connect the motor 49 to the lines L1, L2, L3 to drive the carrier 117 forwardly along the track 111. The contacts A4 also close to form `a holding circuit for the relay A. The arm 57 is put to its rinse position and so the U- pipe 21 is passed over the length of the motor car and jets of water from its nozzles 126 thoroughly wet the motor car.

When the carrier 117 nears the forward end of its travel one of the rollers 56 on one of the arms 54 actuates the lever 53 of the front limit switch 52, thereby causing the contact 188 of that switch to change over from the contact 189 to the contact 190. The relay A is thereby deeenergised, so that contacts A1 to A4 open, and the relay operating coil D/ 1 of the relay D is energised through the normally closed contacts of the rear limit switch 51. The relay D has an operating vdelay time of about 5 seconds, at the end of which time the contact D2 closes. The operating coil B/ 6 of the relay B is thereby energised through closed contacts A5. The armatures of the relays A and B are interlocked to ensure that only one of them can be in its operated position at any one time. When the relay B operates, the contacts B1, B2 and B3 close thereby connecting the motor 49 to the lines L1, L2 and L3, the connections of the

phase windings

181, 182 to the lines L1 and L2 being interchanged as compared with the connections which had previously been made by the contacts A1 and A2. Consequently the direction of drive of the motor 49 is reversed and the carrier 117 is driven rearwardly along the track. The operation of the relay B also opens contacts B4 and closes contacts B5 and B6. l

The aforesaid operation of the front limit switch 52 closed contacts 191 thereof, thereby connecting the red lamp 64 between the lines L1 and N and so causing it to light. When the operator of the machine sees the lamp 64 light he moves the arm 57 to its soap position thereby cutting off the water supply to the jets and closing the contacts 66. The operating coil C/4 of the relay C is thereby energised through the closed contacts B6. The contacts C1, C2 and C3 thereupon close to energise the detergent pump motor 184 from the lines L1, L2 and L3 and detergent liquid is consequently supplied to the pipe 32 whence it issues `as a spray directed on to the motor-car. The contacts C4 close to short-circuit the contacts 66 and so maintain the lamp 64 alight until the contacts 191 and B6 open. Consequently when the front limit switch 52 is changed back to its initial position by the roller 56 on the forwardly directed arm 54 as the carrier moves away from its forward limit of travel, and the contacts 191 are opened, the lamp 64 remains alight until the relay B is de-energised on operation of the rear limit switch 51. The said changing back of the front limit switch 52 also causes contact 188 to change over from the contact 190 to the contact 189. When the carrier reaches the rearward limit of its travel the rear limit switch 51 is operated by the roller 56 on the rearwardly directed arm 54, thereby opening the contacts 51 and so de-energising the operating coils of the relay D and, owing to the consequent opening of the Contact D2, the relay B. The circuit and apparatus thus reverts to its initial state with the

motors

49 and 184 de-energised and the carrier 117 and the detergent pump 39 stopped.

The operating arm 57 is then set to its rinse position, so starting the water jets of the U-pipe 126, and the start button 62 is pressed thereby to cause the carrier to move forwardly and then rearwardly along the length of the track 111 as aforesaid, the operating arm 57 being left in its rinse position so that the motorcar is thoroughly rinsed by the water jets. As the carrier moves away from its rearmost position it changes back the rear limit switch 51 so re-closing the contacts 51.

lt will be noted that the rearward detergent pipe 36 slopes downwardly from its free end towards the pipe 32. This ensures that when the detergent pump 39 stops, the contents of the detergent pipes do not dribble from the pipe 36 on to the motor-car, which would be disadvantageous in that it would cause undesirable marks thereon, but instead they dribble from the lowermost spray holes of the pipe 32 and so do no harm.

The invention is not restricted to the details ofthe foregoing examples. The pressure of the water supply to the nozzles may be increased by the use of a pump, if so desired.

l claim: l. Apparatus for cleaning vehicles, whlch apparatus comprises, in combination, an elongated track, a carrier mounted on said track for movement therealong, a main liquid conduit carried by said carrier for movement therewith, an auxiliary liquid-conduit located wholly above the level of the vehicle to be cleaned and carried by said carrier for movement therewith, means for supplying washing liquid to said main and auxiliary liquid-conduits, said main liquid-conduit comprising two limbs spaced apart for the reception of the width of the vehicle between them and provided with liquid outlets directed into the space between the said limbs whereby liquid may be directed onto the sides of the vehicle, and said auxiliary liquid-conduit extending in a vertical plane which is substantially parallel to the length of the track and being provided with at least one liquid outlet spaced from the plane of the main liquid-conduit and directed towards that plane, whereby liquid may be directed downwardly onto an end of the vehicle while liquid is also being directed onto the sides of the vehicle as aforesaid.

Z. Apparatus for cleaning vehicles, which apparatus comprises, in combination, an elongated track, a carrier mounted on said track for movement therealong, a main cleaning-liquid conduit, an auxiliary cleaning-liquid conduit, a main detergent-liquid conduit, an auxiliary detergent-liquid conduit, said conduits all being carried by said carrier for movement therewith, and means for supplying cleaning-liquid to said main and auxiliary cleaning-liquid conduits and for supplying detergentliquid to said main and auxiliary detergent-liquid conduits, said main cleaning-liquid conduit comprising two limbs spaced apart for the reception of the width of the vehicle between them and provided with liquid outlets directed into the space ybetween the said limbs whereby cleaning liquid may be directed onto the sides of the vehicle, said auxiliary cleaning-liquid conduit extending in a vertical plane which is substantially parallel to the length of the track, being wholly located above the level of the top of the vehicle to be cleaned and being provided with at least one liquid outlet spaced from the plane of the main cleaning-liquid conduit and directed towards that plane, whereby cleaning-liquid may be directed downwardly onto an end of the vehicle while cleaning liquid is also being directed on to the sides of the vehicle as aforesaid, said main detergent-liquid conduit comprising two limbs spaced apart for the reception of the width of the vehicle between them and provided with liquid outlets directed into the space between the said limbs whereby detergentliquid may be directed onto the sides of the vehicle, said auxiliary detergent-liquid conduit extending in a vertical plane which is substantialy parallel to the length of the track, being wholly located above the level of the top of the vehicle to be cleaned and being provided with at least one liquid outlet spaced from the plane of the main detergent-liquid conduit and directed towards that plane, whereby detergent-liquid may be directed downwardly onto an end of the vehicle while detergent-liquid is also being directed on to the sides of the vehicle as aforesaid.

3. Apparatus for cleaning vehicles, which apparatus comprises, in combination, an elongated track, a carrier mounted on said track for movement therealong, a main cleaning-liquid conduit, an auxiliary cleaning-liquid conduit, a main detergent-liquid conduit, an auxiliary detergent-liquid conduit, said conduits all being carried by said carrier for movement therewith, and means for supplying cleaning-liquid to said main and auxiliary cleaning-liquid conduits and for supplying detergent-liquid to said main and auxiliary detergent-liquid conduits, said main cleaning-liquid conduit comprising two limbs spaced apart for the reception of the width of the vehicle between thern and provided with liquid outlets directed into the space between said limbs whereby the sides of a vehicle in said space and aligned with said track may be washed by cleaning-liquid directed directly against Said sides by said outlets, said auxiliary cleaning-liquid conduit extending in a vertical plane which is substantially parallel to the length of the track, being located wholly above the level of the top of the vehicle to be cleaned and being provided with at least one liquid outlet spaced from the plane of the main cleaning-liquid conduit and directed towards that plane, whereby at least one end of the vehicle may be washed by liquid directed downwardly thereagainst by said one liquid outlet while cleaningliquid is also being directly directed onto the sides of the vehicle as aforesaid, said main detergent-liquid conduit comprising two limbs spaced apart for the reception of the width of the vehicle between them and provided with liquid outlets directed into the space between said limbs whereby the sides of a vehicle in said space and aligned with said track may be washed by detergentliquid directed directly against said sides by said outlets, said auxiliary detergent-liquid conduit extending in a vertical plane which is substantially parallel to the length of the track, being located wholly above the level of the top of the vehicle to be cleaned and being provided with at least one liquid outlet spaced from the plane of the main detergent-liquid conduit and directed towards that plane, whereby at least one end of the vehicle may be washed by liquid directed downwardly directly thereagainst by said one liquid outlet while detergent-liquid is also being directly directed onto the sides of the vehicle as aforesaid.

4. Apparatus for cleaning vehicles, which apparatus comprises, in combination, an elongated elevated track, located above the level of the top of a vehicle to be cleaned, a carrier mounted on said track for movement therealong, motor-operated driving means operatively connected to said carrier to drive said carrier along said track as aforesaid, means for stopping the movement of the carrier at a predetermined position on the track, means for stopping the movement of the carrier at a second predetermined position on the track, means for automatically restarting movement of the carrier in the reverse direction a short period after it has been stopped at the second predetermined position as aforesaid, a main cleaning-liquid conduit, an auxiliary cleaningliquid conduit, a main detergent-liquid conduit, an auxiliary detergent-liquid conduit, said conduits all being carried by said carrier for movement therewith, and means for supplying cleaning-liquid to said main and auxiliary cleaning-liquid conduits and for supplying detergent-liquid to said main and auxiliary detergentliquid conduits, said main cleaning liquid conduit comprising two limbs spaced apart for the reception of the width of the vehicle between them and provided with liquid outlets directed into the space between the said limbs whereby cleaning liquid may be directed onto the sides of the vehicle, said auxiliary cleaning-liquid conduit extending in a vertical plane which is substantially parallel to the length of the track, being located wholly above the level of the top of the vehicle to be cleaned and being provided with at least one liquid outlet spaced from the plane of the main cleaning-liquid conduit and directed towards that plane, whereby cleaning-liquid may be directed downwardly onto an end of the vehicle while cleaning liquid is also being directed onto the sides of the vehicle as aforesaid, said main detergentliquid conduit comprising two limbs spaced apart for the reception of the width of the vehicle between them and provided with liquid outlets directed into the space between the said limbs whereby detergent-liquid may be directed onto the sides of the vehicle, said auxiliary detergent-liquid conduit extending in a vertical plane which is substantially parallel to the length of the track, being located wholly above the level of the top of the vehicle to be cleaned and being provided with at least one liquid outlet spaced from the plane of the main detergent-liquid conduit and directed towards that plane, whereby detergent-liquid may be directed downwardly onto an end of the vehicle while detergent-liquid is also being directed on to the sides of the vehicle as aforesaid.

5. Apparatus for cleaning vehicles as claimed-in claim 4, wherein the means for supplying cleaning-liquid and detergent liquid includes a exible pipe which extends from near the center of the length of the track to the carrier and which is supported intermediate in its length by a substantially horizontal arm pivoted on a vertical pivot near the center of the length of the truck for movement in a substantially horizontal plane to hold the flexible pipe against interference with the carrier and the vehicle during operation of the apparatus.

References Cited in the tile of this patent UNITED STATES PATENTS 1,914,739 Gorke June 20, 1933 2,465,562 Hopper Mar. 29, 1949 2,544,066 Chenault Mar. 6, 1951 2,558,472 Wilcox June 26, 1951 2,648,342 Vani Aug. 1l, 1953 2,676,600 Vani Apr. 27, 1954