Air pump apparatus with vibration and sound reducing housing means

Portable, low noise air pump apparatus employing an inexpensive lightweight pump and motor unit, which pumps a pulsed noisy output into a plenum chamber inside a rubber impervious sub-housing which absorbs noise and vibration; and a sound deadening plastics tube which carries the compressed air from the plenum, via a sound absorbing chamber (surrounded by lightweight sound absorbing material which supports the sub-housing) and across an accommodation space to an outlet fitting from which a smooth low-noise compressed air output can be supplied.

This invention concerns air pump apparatus. 
FIELD OF THE INVENTION 
BACKGROUND OF THE INVENTION 
There are kinds of goods comprising pumps (e.g. motor tire inflators and 
air compressors for vehicle horns) which are noisy but for which the sales 
market for such goods is so large and the operational requirements so 
simple that the cost thereof can be minimized by volume mass production. 
However, such pumps are inherently noisy and are not suitable for other 
purposes where noise is detrimental. Additionally, there are requirements 
for relatively small quantities of pump units for special applications 
requiring complex control systems, such as pump units for air pump 
apparatus for powering and controlling pneumatically operated equipment, 
e.g. lifting seats for disabled persons or dentists drills, but such 
specialized pump units are invariably relatively expensive, complex and 
massive. 
SUMMARY OF THE INVENTION 
The problems of noise, expense, complexity and bulk are faced by the 
invention, and to reduce these problems the present invention generally 
provides air pump apparatus comprising: 
(a) a rigid housing 
(b) a sound absorption chamber in said housing 
(c) pump means in said sound absorption chamber 
(d) duct means within said housing for conveying air from said pump means 
wherein 
(e) said apparatus further comprises a sub-housing which is disposed in the 
sound absorption chamber and defines a plenum chamber to which said duct 
means connects; and 
(f) said pump means comprises a pump and motor unit mounted in said plenum 
chamber to discharge air under pressure into said plenum chamber. 
More particularly, the present invention provides air pump apparatus 
comprising an electric motor, a pump, valve means and electrical operating 
means contained in a housing, wherein a sound absorption chamber 
surrounded by sound absorbent material is provided in the housing; wherein 
a sub-housing is located within the sound absorption chamber; and wherein 
the pump and motor form a unit which is located in a plenum chamber within 
the sub-housing. 
The arrangement of the chambers is preferably such that the air, passed 
through the apparatus, is constrained to flow sequentially through the 
chambers, preferably along a reflex path. 
The invention further provides air pump apparatus comprising an electric 
motor, a valve, a pump and electrical operating means contained in a 
housing, wherein the pump and motor are encased and form a unit, wherein 
the housing is an elongate tube in which the unit is located in a plenum 
chamber in a sub-housing by vibration absorbing damping material, and 
wherein the sub-housing is located in the housing by further damping 
material. The plenum chamber is preferably interposed between the pump and 
the valve. 
A filter is preferably included in an air flow path between the sound 
absorption chamber and an accommodation space in the housing. The sound 
absorbent material may constitute the filter or part of the filter. The 
apparatus may include a battery, preferably located in the accommodation 
space. 
The housing preferably comprises an elongate length of tube having end 
closures. A pipe connection fitting, for pumped air, and manually actuable 
control means or connection means to connect with manually actuable 
control means are preferably provided on or exposed via one of the end 
closures. 
The tube is preferably a plastic extrusion. 
The apparatus may form one of a range thereof differing in some respects, 
such as in length, internal arrangement, or end closure configuration, but 
otherwise of similar general structure in which many common components are 
employed. 
The electrical operating means preferably comprises circuitry mounted on a 
circuit board located in the accommodation space, through which space 
there passes a pipe connecting the plenum chamber directly or indirectly 
with the pipe connection fitting. 
The apparatus is preferably arranged so that an inlet flow path for inlet 
air is provided within the housing between a vent in said end closure and 
the pump, so that said circuit board and valve are passed by air flowing 
along the inlet flow path to the inlet duct. 
A battery is preferably located in the accommodation space on a carrier 
which preferably also supports the circuit board, pipe connection fitting, 
control means or connection means, and which may be provided with 
electrical input terminals for re-charging the battery. 
The apparatus may be arranged to deliver air under pressure to the pipe 
connection fitting, or to deliver air under pressure to and withdraw air 
under suction from the pipe connection fitting. 
The user of pump apparatus faces problems with the storage of fittings for 
the apparatus, which problems can be severe in the case of pump apparatus 
for powering aids for disabled users. 
To reduce such problems, the present invention provides pump apparatus in 
which a pump, motor, battery and control valve are located in a rigid 
housing; wherein the housing directly supports a cover assembly, which 
cover assembly includes an openable storage compartment for storing 
fittings and accessories for the apparatus. 
The housing may be cylindrical, and the storage compartment is preferably 
arranged to support the housing against being rolled. 
The invention includes pneumatic support or lifting apparatus such as a 
wheelchair comprising a pneumatically operated device coupled to or 
incorporating air pump apparatus of the invention. 
The relatively light and inexpensive housing enables a lightweight and 
inexpensive compressor unit, of the kind produced for vehicle horns, to be 
employed as the pump and motor unit to be used in situations in which the 
noise produced by such a unit would otherwise be unacceptable.

DETAILED DESCRIPTION 
Referring to FIGS. 1 and 2, each of the embodiments of the pump apparatus 
primarily comprises a housing 11 containing a battery 12, a pump and motor 
unit 13, a plenum chamber 14, a solenoid actuated normally closed valve 15 
and/or 15A or 15B and a circuit board 16. 
Housing 11 includes a rigid cylindrical body 17, a rear end closure 18 and 
a front end closure 19. The body 17 is a length of inexpensive mass 
produced circular cross-section extruded plastics tubing. Each end closure 
is a cover, the front cover 19 being modified to expose certain parts and 
fittings of the apparatus which are mounted on a battery support frame 60. 
The parts include a holder 20 for a motor fuse 40, a holder 21 for a 
control circuit fuse 41, a charge input socket connector 22, a pumped air 
connection fitting 25 for reception of a connector 10D of a pressure 
supply line 10E to a pneumatically actuated lifting device 10F of an aid 
for a disabled person, for example, a wheelchair 10G. An electrical socket 
connector 61 received plug lead connector 10A to a remote handset 10B 
incorporating a combined center-off switch 10C incorporating an up-switch 
23 and a down-switch 24 shown in FIGS. 3 and 4 to 5. A duplicate switch 
10C may be provided at the front cover 19 as indicated in broken lines in 
FIG. 3. Two air inlet vents 26 are also provided in the closure 19, which 
is releasably secured to the frame 60. 
The frame 60 is secured to the body 17 of the housing 11 in an 
accommodation space 62 in the housing. 
The battery 12 is a sealed rechargeable 12 volt battery, having terminals 
27 and 28, and is secured in the frame 60. 
Air pumping 13 is an inexpensive light, but noisy, mass produced 12 volt 
air compressor (of a kind intended for vehicle air-horns) which comprises 
a pump 13A and a motor 13B housed in a casing 63. The front end portion of 
air pumping unit 13, i.e. that portion of the unit 13 in which the 
material, such as rubber, visco-elastic or elastomeric material, which is 
set in the front end portion of a thick walled sub-housing 64 of similar 
vibration damping or absorbent material such as plastics or rubber 
material so that the unit 13 extends in cantilever manner along the 
chamber 14. The remainder of the interior of the sub-housing constitutes 
the plenum chamber 14 and a rear portion of the sub-housing 64 is provided 
by a sealing closure 65. 
The sub-housing 64 and the valve 15 and/or 15A or 15B is or are located in 
a sound absorbing chamber 66 defined by or substantially filled with sound 
absorption material 30, such as plastic sheet backed porous foamed plastic 
or elastomeric material or a fibrous material, which material 30 supports 
at least portions of the valve and housing 64. A pumped-air tube 31 
extends within the chamber 66, is secured to the closure 65 and connects 
the plenum chamber 14 directly or indirectly with a tube 35 to the pumped 
or working air connection fitting 25. Air pumping unit 13 is connected by 
an air inlet supply pipe 33 which is made from flexible preferably 
vibration absorbent material pipe 33 passes through the plenum chamber 14 
and the sealing closure 65 of sub-housing 64 to the sound absorption 
chamber 66 in which the valve 15 and/or 15A is located. An air pressure 
line 36 connects the tube 35 (or possibly the fitting 25 or the chamber 
14) with a pressure sensitive limit switch 37 on the circuit board 16. 
The apparatus is provided with a cover assembly 70 comprising a cylindrical 
fabric cover 71, which surrounds and grips or is adhered to the peripheral 
surface of body 17 of the housing between peripheral flanges 34 on the 
closures 18 and 19, and a storage compartment 72 having a flat bottom 73 
tangential to the housing. The compartment 72 has a lid 74. A handle 75 is 
provided at the top of the assembly 70. The handle may be secured to the 
cover 71 or the body 17. Apertures in the front closure 19 give access to 
the fittings mounted on the battery support frame 60. Removal of the 
closure by releasing fasteners 76 gives access to the battery. 
The circuit board 16 carries circuitry and electrical components of 
electrical operating means which is actuable by manually actuable control 
means which comprises a remote control unit 10B incorporating the up and 
down switches which is connectable via a cable having the plug connector 
10A insertable into the socket connector 61. The first and second 
embodiments of the apparatus differ in that the first embodiment (FIGS. 1 
and 4A, 4B) is controllable to pump air to and suck air from the fitting 
25, whereas the second embodiment (FIGS. 2 and 5, 5A) is arranged only to 
pump air to the fitting 25. Depending upon the embodiment, the operating 
and control means may provide for bi-directional operation of air pumping 
unit 13 employing a circuit such as is shown in FIGS. 4, 4A, 4B or for 
unidirectional operation of the unit employing a circuit such as is shown 
in FIGS. 5, 5A. 
In the first embodiment shown in FIG. 1, the valve 15 is interposed between 
the tubes 31 and 35 and, as shown in FIG. 4, the circuit includes a "down" 
relay 42 controlled by the switch 24, a safety relay 43 controlled by the 
pressure switch 37 and an up relay 44 controlled by the switch 23. In the 
off condition of the circuit (which condition is illustrated in all 
FIGURES) the motor 45 of the unit 13 and the valve 15 are de-energized. 
The battery can be trickle charged via the connector 22 and fuse 41. 
When the up switch 23 is closed, the up relay 44 and the valve 15 are 
activated to energise the motor 45 and open the valve 15 to cause air to 
be pumped under pressure into the chamber 14, to traverse said chamber 14 
and enter the pipe 31 in which it flows forwards within the chamber 66 and 
via the valve 15 and pipe 35 to the fitting 25; and to draw relief air 
into the housing via the inlet vents 26 to flow past the circuit board and 
valve, to enter the front end of the chamber 66 and flow rearwards to the 
rear end, and to flow into the pipe 33 at said rear end and along said 
pipe forwards across the chamber 14 to an air inlet 33A of the unit 13. 
If the pressure limit set by the switch 37 is reached, this switch closes 
to activate relay 43 which de-engerizes the relay 44 shutting off the 
motor, and removes the power supply to the valve 15 so that the valve 
closes. 
When the down switch 24 is closed, relay 42 is activated to energized and 
open the valve 15 without energizing the motor and irrespective of the 
condition of the switch 37, so that air under pressure can flow back from 
the fitting 25 to the vent 26 via the unit 13. 
For operating the unit 13 reversibly, the circuit includes pole-reversing 
relays 50 and 51 and an exhaust switch 53, which switch or a duplicate 
thereof can also be provided in the remote control unit and/or at the 
cover 19. 
Switch 53 is fed via switch 24 so that when both switches 24 and 53 are 
closed relays 50 and 51 are activated to energized the motor 45 with 
reversed polarity of the electrical supply at the same time as the valve 
15 is opened, thereby pumping air from fitting 25 to vents 26 via the 
chamber 14. 
It will be readily appreciated that in the first embodiment when only the 
switch 24 is closed, air under pressure at the fitting 25 can flow back 
via the unit 13 in which the undriven pump serves as an impedance. If 
rapid but unpumped venting of air under pressure at the fitting 25 is 
required in the first embodiment, an additional valve 15A (indicated in 
broken line in FIG. 1) can be connected to the plenum chamber by a further 
tube 38, and a vent selection switch 53 included in the control circuit as 
shown in FIG. 4A. 
In the second embodiment, the valve 15 is omitted and the outlet from air 
pumping unit 13 passes through a mechanical non-return valve 67 and 
through a normally open path through (FIG. 5A) or by-passing (FIG. 5) the 
valve 15B to the pipe 35; and the valve 15B is not connected to the plenum 
chamber by a further tube 38 mounted on the closure 65, but instead opens, 
when energized, a branch port 15C to discharge air from the pipe 35 
directly into the chamber 66 so as to be silenced with minimum flow 
restriction. 
The control circuit is simplified as shown in FIGS. 5 and 5A so that the 
motor is unidirectionally energizable via switch 23 and normal closed 
relay 43, and can be isolated by energization of relay 43 by pressure 
switch 37. The port 15C of the valve 15B remains closed during pumping, 
and at other times unless switch 24 is closed to allow air under pressure 
at the fitting 25 to flow back via the tube 35, the valve 15B, the chamber 
66 and the accommodation space 62 to the vents 26. The valve 15B could be 
inserted into the tube 31 or 35 in the first embodiment as a substitute 
for the valve 15A and tube 38. 
Both circuits may be adapted for direct instead of or as well as remote 
actuation. For example, the switches 23 and 24, or 23, 24 and 53 may be 
located on the front cover 19 instead of in a portable hand-held control 
unit, or, as shown in broken lines in FIGS. 5 and 5A supplementary 
switches e.g. 23B and 24B may be mounted on the cover 19 e.g. as a 
combined "center-off" switch assembly 10C, to enable the apparatus to be 
operated when the remote control unit is disconnected from the socket 61. 
Both circuits are easily adapted for rapid recharging of the battery, 
and/or direct operation with or without a battery, by modification of the 
circuits as shown in FIG. 4B. 
In from FIGS. 1 and 2, the sub-housing 64 is relatively thick walled and is 
made from a solid or otherwise air impervious vibration absorbing 
elastomeric or plastics material; and the sound absorption chamber 66 is 
filled partially with porous packing e.g. the layer 69 which serves to 
support the tubes and the sub-housing 64 as well as to absorb some of the 
noise from the unit 13. Further porous or fibrous material 69A may be 
located in the voids shown around the valve 15 and tubes to substantially 
fill the chamber 66 as indicated in FIG. 2. The annular front end portion 
80 of the peripheral layer of sound absorbent material 30 serves as an 
annular air inlet to the chamber 66 around the front face 81 of the 
foremost sheet plastics layer of the sound absorbent material 30, so that 
the peripheral layer serves as an air filter. 
Further noise/vibration absorption may be provided by the layer 69 and any 
additional fibrous material in the chamber 66. The arrangement of the 
chambers, sound absorbing materials and filtration of the air flows 
provides a smooth flow of pumped air quietly from a noisy and pulsed 
output from air pumping unit 13. The noise reduction is further improved 
by the use of flexible materials which are poor transmitters of sound for 
the tubes 31, 33, 35 and 38. The valve 15, 15A or valves 15 and 15A may be 
located in the chamber 14, but if the valve 15B is located in the chamber 
14, the port 15C will have to be fitted with a tube to convey air out of 
the chamber 14 e.g. to the chamber 66. 
The invention also includes and provides apparatus having any part, 
component, function, mode of operation, or feature of arrangement which is 
novel, or novel in combination with others thereof and is disclosed herein 
or in the accompanying drawings. For example, the invention includes and 
provides pneumatic apparatus including an air pump apparatus wherein the 
pneumatic apparatus includes an air pressure operated device which is 
solely operated by air which is passed through a single line between said 
device and a pump unit of the pump apparatus so that all air flowing in 
said line to and from said device under the control of valve means of the 
apparatus is constrained to flow through a sound absorbing chamber within 
the apparatus, and wherein pumped air from the pump unit is also 
constrained to flow through a plenum chamber in which the pump unit is 
disposed within the sound absorption chamber. Such air flows are 
preferably controlled by the pump unit and actuation of a remotely 
controllable valve.