GB2205361A

GB2205361A - Compact air compressor

Info

Publication number: GB2205361A
Application number: GB08624222A
Authority: GB
Inventors: Ah Soon Lee
Original assignee: Individual
Current assignee: Individual
Priority date: 1986-10-09
Filing date: 1986-10-09
Publication date: 1988-12-07
Also published as: GB8624222D0

Abstract

A compact air compressor (11) having relatively low power requirements, for use by motor cyclists for example, comprises a high speed 12 volt motor (19) in a motor housing (14) driving a shaft (20) to which is secured a cam cylinder (26). The cam cylinder (26) has a helical endless groove (27) around its periphery in which is received a follower pin (30). The follower pin (30) passes through a hole in a cylindrical piston (32) slidingly mounted on the cam cylinder (26) and is slidingly engaged in a key slot (31) in the wall of a compressor housing (12) in the bore (33) of which slides the piston (32). Air inlet and outlet valves (39.40) are disposed in an end cap (13) of the compressor housing (12). When the motor (19) is running the cam cylinder (26) rotates with the shaft (20) and causes the follower pin (30) and hence the piston (32) to reciprocate in the bore (33) of the compressor housing (12), thereby compressing the air therein which is drawn in through inlet (37) and is expressed through outlet (38). <IMAGE>

Description

COMPACT AIR COMPRESSOR.

This invention relates to air compressors.

Conventionally air compressors comprise a motor driven shaft to which is connected a crank driving a piston. However such compressors are relatively bulky and have relatively large power requirements. It is an object of the present invention to provide an air compressor which is relatively compact and has relatively low power requirements such that it may conveniently be of use to, for example, motor cyclists having a 12 volt power supply and limited storage space.

The invention provides an air compressor comprising a driving shaft adapted to be driven by a motor, a piston disposed in a compressor housing, and a rotary cam device engaged by said shaft and said piston, and operable upon rotation of said shaft to reciprocate said piston in said compressor housing axially of said shaft, said compressor housing having air inlet and air outlet valves therein.

The cam device may comprise follower means disposed to engage a cam surface of said cam device. Said follower means may be fixedly located in said compressor housing and said cam device may comprise a cam cylinder movably mounted on said shaft and engaging said piston. Alternatively said cam device may comprise a cam cylinder fixedly located on said shaft and said follower means may be slidingly mounted in said compressor housing and engaging said piston.

In the latter case said piston may comprise a cylinder with said cam cylinder slidingly disposed in said piston cylinder0 Said cam cylinder may have an axial bore adapted to receive said shaft.

The air compressor may also include a motor connected to said shaft, and said motor may be located in a motor housing which is connected to said compressor housing.

Said cam cylinder may have a helical continuous cam groove around its periphery and said follower may comprise a gudgeon pin mounted in said compressor housing and adapted to be received in said cam groove to engage said cam surface therein. Said gudgeon pin may be slidingly received in a slot in said compressor housing and extending longitudinally thereof.

Said piston cylinder may have one end thereof closed.

A hole may be provided in the sidewall of said piston cylinder through which said gudgeon pin passes.

Said air inlet and air outlet valves may be located in a cap part of said compressor housing, and each valve may comprise a valve member biassed by a spring towards a valve seating.

One embodiment of air compressor in accordance with the invention will now be described with reference to the accompanying drawings, in which: Fig. 1 is a general assembly in longitudinal section, Fig. 2 is an end view of the compressor housing, Fig. 3 is a section on line 3-3 of Fig. 2, Fig. 4 is a scrap elevation of the slot in the compressor housing, Fig. 5 is an end view of the motor housing, Fig. 6 is a section on line 6-6 of Fig. 5, Fig. 7 is an enlarged elevation of the cam device, Figs. 8 and 9 are a front elevation and a sectional side elevation of the piston respectively, and, Fig. 10 is an end elevation of the compressor cap with air inlet and outlet valves therein.

Referring now to Fig. 1 there is shown an air compressor 11 comprising a compressor housing 12 in the form of a cylinder, having a cap 13 at one end and a motor housing 14 at the other end. The cap 13, compressor housing 12 and motor housing 14 are secured to each other by four studs 15 which pass through holes 16 in the cap 13, bores 17 in the compressor housing 12 and are received in threaded bores 18 in the motor housing 14. An electric motor 19 is disposed in the motor housing 14, one end of the motor shaft 20 being received in a bearing 21 in the end plate 22 of the motor housing 14 and extending at the other end 23 into the compressor housing 12e An on-off switch 24 for the electric motor 19 is mounted on the motor housing 14, as shown in an exploded view in Fig. 6.

Secured by a grub screw 25 to the end 23 of the shaft 20 is a cam cylinder 26 having a helical, endless cam groove 27 around its periphery, there being a threaded radial bore 28 for the grub screw 25 extending from the periphery of the cam cylinder 26 to an axial bore 29 therein in which the end 23 of the shaft 20 is received. By this means the cam cylinder 26 is caused to rotate with the shaft 20 when the motor 19 is switched on and running. A follower 30 in the form of a gudgeon pin has one end thereof received in the cam groove 27 and is slidingly located in a key slot 31 mounted in the side of the compressor housing 12. A cylindrical piston 32 is coaxially disposed on the outer surface of the cam cylinder 26 so as to be slidable thereon and within the bore 33 of the compressor housing 12, a piston ring 34 being fitted to the outside of the piston cylinder 32.

The gudgeon pin 30 passes through a hole 35 in the wall of the piston cylinder 32 so that as the cam cylinder 26 rotates the gudgeon pin 30 is moved in cam slot 27 so as to reciprocate in the key slot 31 and cause the piston cylinder 32 to reciprocate in the bore 33. As a consequence, suction and compression pressures will be successively created in the bore 33.

At the end of the compressor housing 12 remote from the motor housing 14 is the cap 13, which includes a valve housing 36. The cap 13 comprises an air inlet 37 and an air outlet 38, and an inlet valve 39 and an outlet valve 40 Each valve 39,40 comprises a dome shaped rubber valve member 41 which is biassed by a compression spring 42 towards a valve seating 43 formed in the valve housing 36 or cap 13.

When the piston 32 moves towards the motor 19 and a suction pressure is created in the bore 33 of the compressor housing 12, the air pressure in air inlet 37 will overcome the force of the inlet valve spring 42 and cause inlet valve 39 to open and admit air into the bore 33. The suction pressure and the outlet valve spring 42 will assist in keeping outlet valve 40 closed. As the shaft 20 rotates through 1800 the cam cylinder 26 will rotate through 1800 also and the follower pin 30 and piston 32 will move towards the cap 13 and a compression pressure will be created in the bore 33. In consequence the compression pressure and the inlet valve spring 42 will assist each other in closing the inlet valve 39 whilst the compression pressure will overcome the force of the outlet valve spring 42 to open the outlet valve 40.

By this means a regular supply of compressed air is provided. The compressor is relatively compact for easy storage and transportation and is driven by a high speed 12 volt motor so that it can be powered by a motor cycle or car electrical system, Longitudinally extending cooling ribs 44 are provided around the periphery of the compressor housing 12 to dissipate any heat caused by the air compression, and further ribs 45 are provided on the cap 13 for this purpose.

Claims

1. An air compressor comprising a driving shaft adapted to be driven by a motor, a piston disposed in a compressor housing, and a rotary cam device engaged by said shaft and said piston and operable on rotation of said shaft to reciprocate said piston in said compressor housing axially of said shaft, said compressor housing having air inlet and air outlet valves therein.

2. An air compressor according to claim 1, wherein said cam device comprises a cam cylinder having an axial bore therein adapted to receive said shaft

3. An air compressor according to claim 2 comprising follower means disposed to engage a cam surface of said cam cylinder.

4. An air compressor according to claim 3, wherein said cam cylinder has a helical, endless groove around the periphery thereof.

5. An air compressor according to claim 4, wherein said follower device is fixedly located in said compressor housing and said cam cylinder is movably mounted on said shaft and engages said piston.

6. An air compressor according to claim 4 wherein said cam cylinder is fixedly located on said shaft and said follower means is slidingly mounted in said compressor housing and engages said piston.

7 An air compressor according to claim 6, wherein said piston comprises a cylinder having an axial bore therein in which said cam cylinder is slidingly received.

80 An air compressor according to claim 7 wherein said follower comprises a gudgeon pin having one end thereof received in said cam groove and the other end thereof slidingly received in a key slot secured in said compressor housing and extending longitudinally.

9. An air compressor according to claim 8, wherein said piston cylinder has a radial bore therein through which said gudgeon pin passes

10. An air compressor according to any one of claims 1 to 9, comprising an electric motor connected to said shaft.

11. An air compressor according to claim 10, wherein said motor is located in a motor housing which is connected to said compressor housing.

12. An air compressor according to claim 11 comprising an on/off switch for said motor mounted on said motor housing.

13. An air compressor according to any one of claims 1 to 12, wherein said compressor housing comprises a cap at one end thereof.

14. An air compressor according to claim 13, wherein said cap has said inlet and outlet valves disposed therein.

15. An air compressor according to claim 14, wherein each of said valves comprises a valve member biassed by a spring towards a valve seating.

16. An air compressor according to any one of claims 1 to 15, wherein said compressor housing has longitudinally extending ribs disposed around the periphery thereof.

17. An air compressor substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.