US 2320368 A
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June 1, 1943. w. LEATHERS VACUUM CLEANER ELECTRIC INDICATOR 2 Sheets-Sheet 1 Filed July 11, 1938 o INVE TOR June 1, 1943. w, LEATHERS 2,320,368
VACUUM CLEANER ELECTRIC INDICATOR Filed July 11, 1958 2 Sheets-Sheet 2 MVENZ OR.
' Patented June 1 1943 UNITED I STATES. PAT
, zszoses lZNT OFFICE ELECTRIC INDICATOR Ward Leathers, Haworth, N. J,, assignor to Quadrex Corporation, tion of Delaware Application July 11 L 1 Claim.
\ My invention applies particularly to canister type vacuum-cleaners, i.- e., those having the filter enclosed in a casing along with a motorwhen. the air-fiow is obstructed to the point where the cleaning function at the nozzle is materially impaired, although the cleaner has not accumulated. sufficient dirt to require emptying. 7 4
The object of my invention is to produce an electrical device which will advise the operator of the true working-condition of the machine. It is the objectprimarilyto give notification of the fact that the nozzle is not cleaning at its full capacity and thereby advise the user to shake the filter or to empty the machine. In some of the embodiments of my invention as herein set forth, still further information is provided, such as notification that shaking the filter is not sufficient but that the machine has filled up with dirt to a point where emptying it is imperative. 4
Machines of the type described when in operation have, within the case, chambers of dilferent pressures. First, there is the dirt-collection and filter chamber. Second, there is the chamber between the filter and the air-compression, which latter has the lowest pressure of any point in the machine. Air admitted to the first mentioned chamber by means of a nozzle and cleaning hose maintains a higher pressure than in the second mentioned chamber due to the air impedance of the filter. The differential between these two pressures, however, is variable, depending upon several factors, the most important of which is the accumulation of dirt against the walls of the filter. This invention is concerned with electric indicators for the purpose of giving the operator the measure of this air impedance and operated by the differential between the two said pressures.
My inventionis applicable to canister type vacuum-cleaners of the horizontal-axis type or the vertical-axis type. In order to set forth my invention so that all those familiar with these arts may understand, I have prepared the following specification, to which I have appended drawings, of which:
New York, N.
Y., a corpora- 1938, S erial No. 218,646 ((11. 177-311) Figure 1 is a plan view or elevation of a pneumatic-electric flasher mechanism for use with a normally glowing lamp.
Figure 2 is an inside view of same.
. Figure. 3 is a cross-section of same.
Figure 4 is a detail.
Figure 5 is a cross-section of a thermal flasher unit for same.
Figure 6 is a wire diagram for .same.
for lighting a non-continuousor elevation of a pneulamps.
Figure 13 is the inside of same. Figure 14 is a partial cross-section of same. Figures 15v and 16 are wire diagrams for same. A pneumatic-electric unit I, Figs. 1, 2, and 3, may be mounted in any available location within the case of the machine (in the drawings it is shown substantially actual size). This unit may be mounted at any desired angle, but for purposes of convenience will be hereinafter de- ,scribed as having a top and a bottom. An upper case member 2, and a lower case member 3, hold between them in air-tight manner a flexible diaphragm 4. This diaphragm may be made of sheet bronze, corrugated annularly, it may be of terial. A tube 6 communicates with the pressure-chamber on the under side of the diaphragm, and at its other end communicates with the chamber on the inside, or dirt-receiving side, of the filter. Another tube 1 communicates with the upper pressure-chamber and at its other end communicates with the chamber between the filter and the air-compressor. The diaphragmv 4 is thereby caused to flex proportionately to the differential of the pressures in the said chambers. A push button 8 is firmly joined to the upper side of the diaphragm 4 at the center and is made of insulating material. An aperture Win the upper case member 2 is covered in air-tight manner by a disc of insulating material H. (A top view of this disc is shown in Fig. 4.) A two-way lighting cord l5, wired parallel, with the motor of the machine (as-shown in the wire-diagram, Fig. 6) furnishes Figure 7 is a'plan view or elevation of a modi matic-electric unit for turning on or off twov impervious flexible fabric, or other suitable ma-- as one at the end of the extension tube adjacent the cleaning nozzle, as fully set forth in my applicatlon for Letters Patent No. 216,011, filed June 27, 19 38. One of the two lines i is in;- terrupted by the electric mechanism mounted in and on the disc ii. One end of the interrupted wire is joined to a binding post I! which electrically contacts a conductor strap I8 on the top of the disc. II. The strap I8 is riveted to a spring contact member IS on the under side of the disc by a rivet 20, thereby establishing an electrical path therethrough. The other end of the strap i8 is similarly held by a rivet through the disc to an inner electrical thermal-unit 2|, shown in Figs. 1 and 5. This thermal unit comprises a non-movable conductor-strap and contact 22, and a thermal bi-metal strap 23 devised in a manner common to flashers, which in practice make lamps glow at intervals. The
strap 22 is insulated from the strap 23 by means of a separation strip 24.. The bi-metal strap is surrounded with insulation and nichrome windbinding posts I! and 30 which are electrically joined to conductor straps 3| and 32, respectively. Across the other ends of these straps is joined, on the upper side oi. the disc I I, an electrical resistance 32 and on the under side a spring contact mechanism 33. The purpose of this arrangement is to light a non-continuous-glow lamp at such times as the differential-pressures on the diaphragm call for such indication. When the pushbutton 8 raises the spring 33 until contact is established, the resistance 32 isshunted out of the lamp circuit and the lamp glows.
The diagram, Fig. 11, shows a combination of the principles set forth in Figs. l'to 5 and the diagram Fig. 6, with those of Figs. '1 to 9 and diagram Fig. 10. It has for its purpose the lighting and flashing of a non-continuousglow indicating lamp. The resistance 32 of Figs. 7, 8, and 9, is used for maintaining voltage on the lamp below the glow-point. When the pushbutton 8 establishes a contact by means of the spring member 33 it shunts out the resistance 32 which is in series with the lamp L and flasher 2|. The flasher mechanism of Fig. 5 then comes into action. 'The resistor. 32 is of lower resistance than that of the winding on the fiasher unit.
ing. The winding is joined at one end to strap.
22, the other end to23, and the parts are so disposed that when the strap 23 reaches a sufficient temperature a contact is established between 22 and 23; The thermal strap 23 electrically contacts another conductor strap 25 on the inside of the disc.- This strap has an electric contact point 26 normally in contact with a similar point on the spring member IS. The conductor strap 25 is electrically joined by means of a binding post- 30 through the disc II to the otherend of the interrupted wire of the pair ii. The above recited electrical parts are so disposed that the push-button' 8 on the diaphragm 4- so engages the spring member l9, that when the button moves upward from an increased differential pressure in thepressurechambers, electric contact is broken between the parts 25 and 23. The current supplied tothe continuously glowing lamp is then interrupted and is obliged to find its way through the flasher unit 2!. Thus the lamp flashes by a well-known cycle, indicating to the user that the pressure in the filter chamber is toohigh, that is, that the filter needs shaking or the machine requires emptying. It should be noted that this electric indicator and all modifications of same hereinafter described, operate on the principle of maintaining sumcient voltage in the lamps (when the machine is in use) that interruptions for indicating purposes. whether for causing lamps to glow or cease to glow, require no breaking, by the diaphragm mechanism, of more than a part of the full lamp voltage. The purpose of this arrangement is to avoid unnecessary switches with quick make-andbreak and wide gap, and in general to avoid sparking at the contacts which would destroy them. However, I wish it understood that where resistances are used, as described in the remainder of this specification, for maintaining sub-voltages in non-glowing lamps, they may be replaced by condensers, if desired, in order to reduce sparking at points of make-and-break.
A very simple, modified form of my pneumaticelectric-indicator is shown in Figs. '7, 8, and 9, together with the diagram, Fig. 10. The interrupted wire of the parallel pair I5 is joined to A further and highly desirable modification of my invention consists of two indicator lamps, one green and one red (or of other suitable colors) for giving the operator a more complete understanding of the cleaning characteristics of the machine while in operation. This arrangement is set forth in Figs. 12, 13, and 14, and the diagram of Figs. 15 and 16. One of the parallel cords i5 is interrupted as in Fig. 1, but the interrupted line is then divided into lines and 4| between the pneumatic-electric unit and the'two lamps. The other line serves the lamps in common (see Fig. 15). The line I5 is joined to a binding post 42 on the upper side of the enlarged disc ii which by means of a strap 43 and by a rivet 44 is joined electrically to a spring contact member 45 on the under side. The binding post is further joined electrically, by means of a spring I 46, to the center of a carbon-resistance 41 mounted on the top of the disc. This carbon resistance has metal binding caps on either end to which the wires 40 and 4| are joined. It further has a metal contact-ring at the center, contacted by the spring 46. It further has supports on either end which serve as electric conductors which lead, by means of rivets,,through the disc i l to the spring contact members 50 and 5i. In operation this device works as follows:-Contact is normally maintained between the spring contact members 45 and 50 and not with 5|. When the pushbutton 8, impinging against the under side of the spring member 45, raises it a predetermined distance, it establishes contact with the spring member 5|. When it raises a still further distance it breaks its contact with the spring member 50. The spring members 50 and 5| are provided with' suitable stops for this purpose. Current supplied over the spring member 45 maintains a full voltage current supply in a green lamp 55, while the red lamp 54 is supplied with current through one-half of the carbon resistance 41. When 45 makes contact with 5i the resistance is shunted out and the red lamp glows. When contact is broken between 45 and 50 the green light ceases to glow, being supplied with current only through the other half of the resistance 41. Thus-a green lamp burns on the machine when in use to indicate that the cleaning at the nozzle is-of full and satisfactory character. When the impedence in the filter reaches such predetermined point that the nozzle function is less than is desired, the red light 54 glows beside the green lamp 55. At this point the operator is advisedthat full efllciency may be reestablished by shaking the filter. When the machine is neglected and the dirt is permitted to accumulate to a point where air impedence makes the machine no longer truly serviceable, at such predetermined point, the red light alone glows on the machine indicating to the operator that it must be emptied.
By properly choosing the ohmic value of the resistor 41 the potential existing across any pair of open contacts may be appreciably reduced. Thus there will be no danger of a dust explosion in the vicinity oi. the apparatus since the contacts ar spark-proof and arc-proof due to the low potential existing thereacross.
Having set forth my invention so that all those familiar with these arts may understand it, and apply it by means known to common practice, I
wish it understood that any such variations in;
practice fall within the spirit of my invention.
WhatI claim is: An indicating device for vacuum cleaners having a dust filter comprising a casing providing a an extent that the lamp ceases to be incandescent,
connection to the outlet side of the dust filter, a
pair of indicating lamps disposed exteriorly of the casing, a source of current supply therefor, a pair of resistances each being of an ohmic value capable of limiting the current flow through a respective lamp when placed in series therewith to such a normally closed circuit establishing a flow of current through one of said lamps to cause the same to become incandescent, a normally closed circuit including one of said resistances and the other lamp, a two-way switch operable upon actuation thereof for first shunting said last mentioned resistance from its respective circuit to cause said other lamp to become incandescent concurrently with said first mentioned lamp and for secondly opening said first mentioned circuit, and means operatively connecting said diaphragm and switch.