US 3853086 A
In a vacuum cleaner employing a removable dust collector, a device for signalling or indicating when such dust collector should be removed to be cleaned or replaced by a new dust collector. The device is operable to produce such a signal or indication when the vacuum cleaner is not being used to perform cleaning. When the vacuum cleaner is being prepared to start a cleaning operation by connecting appropriate cleaning tools thereto, the signalling device can be observed at such time to determine the need to clean or replace the dust collector before the vacuum cleaner is connected to a source of electrical supply.
Claims available in
Description (OCR text may contain errors)
United States Patent Asplund Dec. 10, 1974 [541 DEVICE FOR SIGNALLING NEED FOR 338L652 5/1968 Schaefer et al. 116/114 AD CLEANING OR REPLACING SUCTION 3,587,515 6/1971 Anderson l l6/l14 AD 3,678,882 7/1972 Kinsella 116/114 AD CLEANER DUST BAG  Inventor: Ivar Asplund, Stockholm, Sweden Przmary ExammerLou1s J. Capoz1  Asslgneez Aktiebolaget Electrolux, Stockholm,
Sweden 22 Filed: Feb. 9, 1973 ABSTRACT PP 331,116 In a vacuum cleaner employing a removable dust collector, a device for signalling or indicating when such  Foreign Application Priority Data dust collector should be removed to be cleaned or re- F b 11 1972 S d 1636 72 placed by a new dust collector. The dev1ce 1s operable e we en I to produce such a signal or indication when the vacuum cleaner is not being used to perform cleaning. g 116/114 When the vacuum cleaner is being prepared to start a i 114 AD 70 cleaning operation by connecting appropriate cleaning 0 care 1 16/1 15/339 6 tools thereto, the signalling device can be observed at such time to determine the need to clean or replace 56 R f d the dust collector before the vacuum cleaner is con- 1 e erences l e nected to a source of electrical supply.
UNITED STATES PATENTS 3,119,369 1/1964 Harland et a1. 116/114 AD 8 Claims, 2 Drawing Figures 32 7 28* 26 l l 6 /0 /7 1 43 f- 2/ 1 2 47 20 5 W H a 1 I 6 I 4 1 1a I tit 45 l i l l ,6 x L. Z
DEVICE FOR SIGNALLING NEED FOR CLEANING ()R REPLACING SUCTION CLEANER DUST BAG This invention relates to a signalling device for a vacuum cleaner having a dust collector and a piston which is movable in dependence on a pressure difierence, one end of the piston being connected with the inlet side of the dust collector and the other end thereof being connected with the outlet side of the dust collector.
In signalling devices of the type referred to the pressure difference between the inlet and the outlet sides of the dust collector is used to move the piston a distance corresponding to the magnitude of the pressure difference. When the dust collector has become clogged so that the need to replace it is necessary, the pressure difference has reached such a magnitude that the piston has moved to a position indicating that such replacement of the dust collector should be done. When the motor-fan unit of the vacuum cleaner is not in opera tion, no such pressure difference will occur and the piston will remain in an initial position. Thus, if the vacuum cleaner is to be used after having been put away for some time, it has to be connected to the source of electrical supply and be started before any indication is obtained to show that the dust collector must be replaced. Then the vacuum cleaner must again be disconnected and be placed in a position suitable for replace ment of the dust collector.
The purpose of this invention is to remove the abovementioned drawbacks and to provide a signalling device by which an indication of the degree of filling of the dust collector is obtained also when the vacuum cleaner is not in operation. Thus, it will be possible already before the cleaner is put into use to ascertain whether the dust collector should be exchanged and re placed before the vacuum cleaner is used and also whether a supply of fresh dust collectors should be obtained by subsequent exchange.
The signalling device according to the invention is generally characterized by a blocking device by which the piston, after movement thereof, is retained in the position reached; and by another device which automatically releases the blocking device when the dust collector is made accessible so that it can be replaced.
In a preferred embodiment of the signalling device according to the invention the connection between one end of the piston and the inlet side of the dust collector is provided by a channel having a filter and a chamber,
receive the dust collector 8. The dust collector 8 comprises a filter 7 in the form of a bag fabricated from air permeable material like paper, for example, and a mounting plate 6 having an opening 5. The open end of the bag 7 is fixed to the plate 6 which serves as an end cover for the dust collector. The mounting plate 6 is detachably mounted in position in the space 12 against wall members therein, as shown in FIG. 1, with the tubular member 13 projecting through the opening 5 in the mounting plate 6. About the tubular member there is provided a sealing ring 14 which is in air-tight sealing relation with the mounting plate 6.
A signalling device embodying the invention is mounted in the front end cover 10. The device comprises a cylinder 17 formed of transparent material like plastic, for example, and a piston 18 which moves in the cylinder. In both ends of the piston seals 19 are provided. By attachment means 20,21,22 and 23 a spring 24 is secured to the piston 18 and to a part 25 of the end cover 10. The spring tends to move the piston 18 to its initial position shown in FIG. 2.
To prevent turning or rotating movement of the piston .18 with respect to the cylinder 17, the piston has a projection 26 extending into a groove 27 in a stationary sleeve 28.
The end cover 10 has a sight glass 29 formed of transparent material like plastic, for example. Through the sight glass and the transparent cylinder 17 the position the latter having a leakageopening to the ambient. In
this way dust is prevented from penetrating into the piston to jeopardize the function of the piston and the blocking device.
Additional characteristics and advantages of the invention will be seen in the following description, in which reference is had to the accompanying drawings.
FIG. 1 is across sectional view of a signalling device embodying the invention taken on line 1'-l of FIG. 2.
FIG. 2 is a longitudinal sectional view taken on line 2-2 of FIG. 10 To illustrate the device as clearly as possible, FIG. 2 illustrates details at different longitudinal sections. In FIGS. 1 and 2 corresponding details are referred to by the same reference numerals.
In the drawing, a front end cover 10 of a vacuum cleaner 9 is shown, only a portion of the casing 11 of the vacuum cleaner being illustrated. The front end cover 10 is formed with a central opening 16 at which of the piston 18 can be seen. For this purpose suitable indicia or markings 18' are provided at the outside of the piston 18. These markings may be in the form of figures or other symbols or areas having different colors.
Along part of its outer surface the piston 18 has grooves or recesses 30 coacting with a blocking device, which comprises a wire spring 31 whose one end extends towards the grooves of the piston through an opening 32 in the cylinder 17. The grooves have elled surfaces 33. When the piston 18 of FIG. 2 is moved to the left, the wire spring 31 will slide on a bevelled surfacef33 and gradually engage with successive or subsequent grooves Then, against the action of the spring 24, the blocking device retains the piston by the last reached groove:
The wire spring 31 is attached to a bracket 34 which, by a shaft 35, is pivotally joumalled inside the end cover 10. The bracket 34 has an arm 36 which in the position shown in FIG. 1 abuts a stop 37 attached to the region a hollow tubular member 13 extends inward therefrom. A suction hose (not shown) is adapted to be casing 11. In this position, which the arm 36 assumes when space 12 in casing 11 is closed by the front end cover 10, the wire spring 31 is in engagement with the grooves 30 of the piston 18. When the cover 10 is opened, for instance, to replace a dust collector, the arm 36 becomes free and the bracket 34 moves away from the piston 18 by the action of a spring 38. Then the wire spring 31 is brought out of engagement with the grooves 30 and the piston 18 can, under the action of the spring 24, return to its initial position. This means that each time the dust collector of the vacuum cleaner is exchanged, the signalling device is reset to zero position and thereafter can indicate the degree of filling of the fresh dust collector.
As will be seen in FIG. 2, the left end of the cylinder 17 is connected to a channel 39. When the end cover It) assumes the position shown in FIG. l, the channel 39- communicates via another channel 3% with that part of the space 12 of casing 111 which is outside the dust collector. The right-hand end of the cylinder 17 has a channel 40 which communicates with another channel 41. The channel 41 is made in a thick wall part 42 of-a cover 43, which is placed near the signalling device. The channel 41 communicates with an annular channel 44 disposed about the tubular member 13 and having an annular filter 45. The signalling device is in communication with the suction passageway 15 through the filter 45 and another passageway 46. Thus, the pressure difference, which depends on the different pressures at the inlet and the outlet sides of the dust collector, will act on the piston 18.
The purpose of the filter 45 is to prevent dust from penetrating into the cylinder 17. If this should happen the friction of the piston 18 against the inner surface of the cylinder 17 could be changed substantially so that incorrect indications would occur. Further, dust could enter into the grooves 30 of the piston and cause an unsatisfactory function of the blocking device. It is however also important in a device of this type to prevent the filter 45 from becoming clogged by dust, which would considerably change the pressure conditions in the channels 44 and 41.
To avoid the last-mentioned inconvenience, a chamber 47 is arranged between the filter 45 and the passageway 46, the chamber 47 communicating with the ambient by a leakage opening 48. The diameter selected for the leakage opening 48 is as small as possible considering the fact that the pressure in the chamber 47 must always be a little greater than the pressure at the opening of the passageway 46 in the suction passageway 15. Thus, in use of the vacuum cleaner there will continuously be a small flow of air through the leakage opening 48 into the chamber 47 and through the passageway 46 to the suction passageway 15. Thus, dust from the suction passageway 15 cannot enter the chamber 47. Because the pressure of the ambient air can be considered to be constant, this pressure will form a reference pressure in the chamber 47 and will not have any influence on the function of the signalling device since the latter all the time operates as a comparing device with respect to the pressures in the suction passageway 15 and in the space 12 of casing 11 outside the dust collector. Pressure changes in the suction passageway 15 will thus influence unambiguously the pressure in the chamber 47 but the air passing through the filter 45 to the signalling device will all of the time come from the leakage opening 48.
1. A signal device for a vacuum cleaner having a mo tor-fan unit, a suction opening and a dust collector adjacent thereto operatively connected to said motor-fan unit comprising: a passageway having a transparent portion, means connecting one end of said passageway to the inlet side of said dust collector and means connecting the other end of said passageway to the outlet side of said dust collector, a piston movable at least in the'transparent portion of said passageway in dependance upon the pressure difference between said'inlet and outlet sides of said dust collector to indicate the amount of accumulation of material in said dust collector, a blocking device co-acting with saidpiston to retain thepiston in the position reached after movement in one direction in said passageway, and means connected to said blocking device for automatically releasing the latter from said piston when the dust collector is made accessible for exchange.
2. A signal device as set forth in claim 1 wherein said piston is provided with a series of grooves extending transverse to the longitudinal axis of said piston, and said blocking device includes a wire spring coacting with a selected groove upon the movement of the piston to a position in said passageway.
3. A signal device as set forth in claim 2 further comprising a bracket having said wire spring thereon, and an openable cover closing the dust collector of the apparatus, said bracket being pivotally arranged on said cover whereby when said cover is opened said wire spring is moved out of said selected groove.
4. A signal device as set forth in claim 3 further comprising another spring which urges said wire spring to a position away from said piston when said cover is opened and to a position abutting said piston when said cover is closed.
5. A signal device as set forth in claim 1 further comprising a resilient means operatively connected to said piston which nonnally urges said piston to its initial position, but subject to the action of said blocking device.
6. A signal device as set forth in claim 1 wherein the connection means between one end of said passageway and the inlet side of the dust collector is provided with a channel having a filter for the passage of air to said piston.
7. A signal device as set forth in claim 6 wherein the side of said filter which is adjacent to the inlet side of said dust collector constitutes a chamber, a passageway connecting said chamber to said inlet side, and a leakage opening from the chamber to the outside of the device thereby communicating with the ambient.
8. A signal device as set forth in claim 1 further comprising indicia on an outer surface of said piston which is visible through said transparent passageway of the device.