[0001] The invention relates to a compressor in accordance with the preamble of claim 1.
[0002] Apparatus for compressing gaseous fluids such as air in enclosed spaces or containers
(e.g. balls, vehicle tires) or for removing gaseous fluids such as air from an enclosed
space e.g. for creation of a vacuum, work mostly with displacement bodies which either
move back and forth (a piston compressor) or rotate (rotating piston compressor) and
in so doing are able to withdraw gaseous fluid from a space or force it into a space.
[0003] The known compressors normally have as their drive an electric or combustion engine.
Their utilization is therefore necessarily dependent on the availability of a power
source such as electrical current or fuel for operating the engine. The engine makes
the compressor more expensive and makes its utilization dependent on the availability
of the power source.
[0004] Such problems are avoided if the compressor is driven with muscle power. Examples
of this are a bicycle pump and a hand or foot pump to pump up automobile tires. In
these a piston equipped with piston rings is moved back and forth within a cylinder,
the piston being firmly attached to a rod at whose end a handle or a pedal is mounted.
In most cases the cylinder and the piston are made of metal or a plastic, the piston
rings are normally made of a polymer compound. The fluid control takes place by means
of a simple check- or hand valve.
[0005] A muscle-power driven compressor of the known bicycle pump type can indeed be operated
without power source, but has the disadvantage that the efficiency and the performance,
i.e., the achievable pressure, is relatively low. Connection of such a compressor
to an existing mechanical energy source is scarcely possible, because it normally
delivers this energy through a rotating shaft and because this rotational movement
cannot he used directly for the known hand and foot pumps. Because the force to be
applied at a predetermined pressure is proportional to the face area of the piston,
this face area is limited in its size. In order to nevertheless be able to displace
the largest possible quantity of fluid with a single movement, the cylinders would
have to be made relatively large and thereby would make the hand or foot pump impractical.
A complete stroke movement cannot be made rapidly because of the great stroke length
and, for piston seals or valves which do not operate without leakage loss, a portion
of the fluid to be compressed can escape into the ambient even during the compression
process. For these reasons the known hand or foot pumps are so limited in their efficiency
and performance that pressures of up to 10 bar cannot be generated so that they are
unsuitable, for example, for pumping up racing bicycle tires.
[0006] The object of the invention is to provide a practical compressor, which is usable
independently of an engine having a special power source and is suitable for generation
of high pressures.
[0007] This object is accomplished in accordance with the invention by the characterizing
portions of Claim 1.
[0008] The compressor according to the invention can be driven either periodically by muscle
power or continuously by mechanical drive and makes it possible to achieve high pressures
and a high compression performance with low force application.
[0009] If the displacement body of the compressor according to the invention is a piston
which is moveable back and forth via the drive shaft and a connecting rod inside a
cylinder in the manner known for reciprocating piston compressors, then during each
rotation of the rope pulley the working space is filled precisely once and the fluid
is compressed in the compression stroke. The number of possible compression strokes
from a single pull at a free rope end depends only upon the number of turns of the
rope around the rope pulley. If the drive shaft has once been set into rotation, the
first overrunning clutch between rope pulley and drive shaft prevents additional rope
from being unwound from the rope pulley, simply by virtue of the mass inertia of the
moving parts or that rope is again wound up in the opposite direction after complete
unwinding. If the compressor takes the form of rotating piston compressor or Roots
compressor, then the rotational inertia moment of the moving parts is generally greater,
relative to its form as a reciprocating piston compressor and the first overrunning
clutch is therefore all the more necessary.
[0010] By the addition of the disc- or wheel shaped rotary body, which can be coupled to
the drive shaft via the second overrunning clutch, the invention makes it possible
to cause the drive shaft to be set into continuous rotation by a mechanical drive.
The compressor can therefore not only simply be driven manually, but can also be simply
connected to an engine shaft or a wheel. Overrunning clutches of the above described
kind are known in themselves, cf German magazine: dhf 12/68 issue, F. Dahmen: Freewheel
clutches -- method of operation, design, and possibilities of application pp. 64-69.
[0011] Thus the compressor according to the invention is equipped with a dual drive and
enables the achievement of high pressures both with manual and with mechanical drive.
The compressor according to the invention is therefore usable where known manual compressors
such as hand or foot pumps are not adequate because of too low performance. The utilization
of a dual drive in an apparatus for pumping up pneumatic tires of bicycles, automobiles,
etc. is known in itself, see, for example, Swiss Patent 103362, but not in conjunction
with the drive for a compressor via two overrunning clutches, either of which can
be utilized.
[0012] Advantageous embodiments of the invention are the subjects of the dependent claims.
[0013] If in an embodiment of the invention a rope pulley and a housing of the compressor
are connected to each other by spring actuator, then the rope unwound through manual
pull on the rope end can be rolled up again on the rope pulley by the spring actuator
which causes the rope pulley to rotate in the opposite direction. Because the rope
pulley is then decoupled from the drive shaft by means of the first overrunning clutch,
even a relatively small spring actuator can rewind the rope rapidly on the rope pulley.
Thus the time delay between two manual pulls on the free rope end for compressing
a fluid can be kept relatively short.
[0014] If in a further embodiment of the invention the spring actuator uses a spiral spring,
one end of which is connected to the rope pulley and the other end to a housing for
the compressor, the spring actuator can be integrated into the rope pulley in space
saving manner. The spiral spring can simply be connected at its ends to the rope pulley
and the housing, respectively, the wound-up form of the spiral spring making it possible
to achieve a plurality of rotations during spring excursion, without the spring force
varying much throughout the spring excursion.
[0015] If in a further embodiment of the invention the rotating body is a friction roller,
then the compressor can be simply driven by pressing the friction roller against a
rotating wheel or a rotating shaft.
[0016] If in a further embodiment of the invention the rotating body is a spur gear, then
the compressor can be simply driven by engaging with it a worm gear on a rotating
shaft or by driving the spur gear by means of a chain which can be driven via pedals
similarly to a bicycle.
[0017] If in a further embodiment of the invention there is provided a holder serving as
a stop for holding the compressor in position, which can, for example, be attached
to the housing of the compressor, then the compressor can be held in place, for example,
by a foot while the free rope end is pulled with one hand.
[0018] If in a further embodiment of the invention the free end of the rope is provided
with a handle, then the pull on the rope end required for compression can be achieved
simply and comfortably with one hand.
[0019] If in a further embodiment of the invention the compressor produces high pressure
air and the compressor is of small size and an adjustable pressure limiting device
is located between the compressor and a compressed air consumer, then the compressor
can be comfortably transported and applied anywhere where highly compressed air is
needed, with the adjustable pressure limiting device preventing the pressure in the
compressed air consumer from exceeding a desired value.
[0020] If in a further embodiment of the invention there is provided, as the pressure limiting
device, dead space of adjustable size inside the compressor, then the pressure limiting
device can be provided simply and reliably. For a given dead space of the compressor
a malfunction of the pressure limiting device, in the sense that the actual pressure
can exceed the desired pressure, is impossible.
[0021] If in a further embodiment of the invention an adjustable pressure relief valve is
provided as the pressure limiting device, then there can be used as pressure limiting
device an inexpensive standard component which is of compact construction and can
be easily connected to the cylinder or a cylinder head.
[0022] If in a further embodiment of the invention the holder is a swivel bracket for pivotable
attachment of the compressor to the frame of a bicycle, then the compressor can be
simply driven by its inward pivoting and by a wheel of the bicycle, most conveniently,
for example, during downhill travel of the bicycle.
[0023] If in a further embodiment of the invention the compressed air consumer is a tire
of a bicycle or a compressed air storage container attached to the frame of the bicycle,
then the tire of the stationary bicycle can be pumped up by pulling on the handle
or, during downhill travel of the bicycle, the compressed air storage container can
be filled without exertion by the cyclist on the bicycle and then the compressed air
can be used later to pump up the tire.
[0024] Exemplary embodiments of the invention are described more fully in what follows with
reference to the drawings. There is shown in
- Fig. 1
- a cross-sectional view of a compressor according to the invention in the form of a
reciprocating piston compressor,
- Fig. 2
- a cross-sectional view of a compressor like that in Fig. 1, but here held in place
via a holder by means of a shoe and to whose discharge a compressed air conduit is
attached which is connected to a bicycle tire,
- Fig. 3
- a front view of a bicycle with a compressor which is connected to the bicycle by a
swivel device and whose output is connected by a compressed air conduit to a compressed
air storage container on the bicycle, and
- Fig. 4
- the use of the compressor according to the invention in a refrigerating plant.
[0025] In Fig. 1 there is shown a compressor for gaseous fluids collectively designated
as
10, in a preferred embodiment as a reciprocating piston compressor, which is provided
with a crankcase
12 and a drive shaft
14 journaled in the crankcase
12 which can be driven optionally either via a rope pulley
16 or a friction roller
18 and which is connected via a connecting rod
20 with a piston
22 which is moveable back and forth in a cylinder
24 by rotation of the drive shaft
14. At the head end
26 of cylinder
24 opposite drive shaft
14 a cylinder head
28 is attached on which there is mounted an intake valve
30 and a discharge valve
32.
[0026] On rope pulley
16 a rope
36 is wound up in a groove
34 on the circumference of the rope pulley
16, with a first, free rope end
38 connected to a handle
40 shaped as a ring and with a second rope end attached to the rope pulley
16. In a recess
42 in a lateral surface of the rope pulley
16 a spiral spring
46 is wound up, with a first end
41 firmly attached to the rope pulley
16 and a second end
43 via a lid
50 to the crankcase
12. The rope pulley
16 and the friction roller
18 are connected to the drive shaft
14 by overrunning clutches
52 and
56, respectively. When the drive shaft
14 is driven by the rope
36, the friction roller
18 freewheels with it. The friction roller
18 can exert its drive force only in a single direction because in the opposite rotating
direction of the friction roller
18 its overrunning clutch becomes effective. The overrunning clutches are so-called
ratchet brakes or sleeve clutches of known type.
[0027] The peripheral surface
58 of friction roller
18 is concavely curved in order to assure a large contact area, for example when laid
against a bicycle tire. A sleeve bearing
60 in the form of a T-bushing for the rotatable bearing of drive shaft
14 is mounted in crankcase
12 and bears with a head end against a crank arm of drive shaft
14. A crank pin
64 is connected to crank arm
62 of drive shaft
14 eccentrically with respect to the axis
A of the crank shaft
14. Rotatably seated on crank pin
64 is a connecting rod end
66 in the form of an eye. The connecting rod end
66 is shrink fitted onto the connecting rod, but the connecting rod end
66 can also be made of a single piece together with the connecting rod
20. The other connecting rod end is connected to the piston
22 by means of a pivotable connection (not shown). The crankcase
12 is closed by a lid
70 at one head end
71 of the crankcase
12 so that there is formed a space which is completely enclosed by the underside of
piston
22, the inner wall of cylinder
24, the crankcase
12, and the lid
70.
[0028] The crankcase
12 in which the drive shaft
14 is rotatably supported by sleeve bearing
60 has at its outer end a chamber
49 which contains the rope pulley
16 and is closed by the lid
15 which is detachably connected to the crankcase
12. The rope
36 is led to the outside through a passage
74 in crankcase
12, where its free end
38 is connected to handle
40.
[0029] At the location of the friction roller
18, which is located on drive shaft
14 approximately midway between the rope pulley
16 and the crank arm
62, the crankcase
12 is partly open along its circumference, so that the friction roller
18 protrudes here radially, i.e. partly or freely accessible, so that it can be set
into rotation through frictional contact with some rotating element (not shown in
Fig. 1). The passage
74 is displaced circumferentially by 180° with respect to the exposed portion of friction
roller
18.
[0030] When the rope
36 is wound up on rope pulley
16 and is pulled at the free rope end
38 by means of ring
40, the rope pulley
16 turns in one direction of rotation about an axis
A of drive shaft
14 relative to the crankcase
12. The overrunning clutch
52 locks up in this direction of rotation so that the drive shaft
14 also turns about axis
A with the same rate and direction of rotation. The crank pin
64, connected to the drive shaft
14 by crank arm
62, which is connected in rotational linkage to the connecting rod end
66 of connecting rod
20, has the effect that the piston
22, which is connected in rotational linkage to the other connecting rod end, moves
back and forth inside cylinder
24.
[0031] When the piston
22 is moved toward the cylinder head
28, the discharge valve
32 opens as soon as the gaseous fluid in the cylinder
24 has a higher pressure than exists on the discharge side. When the piston moves away
from cylinder head
28 the discharge valve
22 closes and the intake valve
30 opens as soon as the gaseous fluid in the cylinder
24 has a lower pressure than prevails at the intake valve
30. In the usual case the pressure prevailing at the intake valve
30 is the ambient pressure.
[0032] At the upper dead center of piston
22 there remains a somewhat compressed fluid in a dead space following the compression
stroke. If the pressure of the fluid in the dead space following the compression stroke
is so high that, in the following suction stroke no additional fluid is drawn in through
the intake valve due to the large quantity of the fluid from the dead space, because
the pressure no longer falls below the ambient pressure, the compressor
10 no longer delivers. The dead space can easily be varied, e.g. by an adjusting screw
thread
23 between cylinder
24 and cylinder head
28.
[0033] If the rope
36 is completely unwound from rope pulley
16 then drive shaft
14 which has been set into rotation can continue to rotate freely due to the overrunning
clutch
52. if, in so doing, no additional corresponding pulling force is exerted upon ring
40, the spiral spring
46 which was placed under tension through unrolling of the rope, turns the rope pulley
16 in the opposite direction of rotation in which the overrunning clutch
52 does not lock the rope pulley
16 up and thereby again winds the rope
36 up on the rope pulley
16. The process of winding up and unwinding of rope
36 on the rope pulley
16 can be repeated as often as desired.
[0034] The friction roller
18 can be driven by being pressed against a rotating bicycle tire or the like. Basically,
any rotating shaft or any rotating wheel can be used as the power source for driving
the compressor
10. Rotation of friction roller
18 drives the compressor
10 via drive shaft
14 in the same way as rotation of the rope pulley
16, although continuously rather than periodically.
[0035] According to Fig. 2 the compressor
10 can conveniently be held in place by shoe
76 via a holder
75 when, for example, the ring shaped handle
40 is pulled away from the compressor by one finger. The discharge valve
32 can be connected to a bicycle tire
78 through a pressure hose
77. When the handle
40 is pulled, air from the outside is drawn in through intake valve
30 and pumped through discharge valve
32 and pressure hose
77 into the bicycle tire
78. When handle
40 is no longer pulled, rope
36 is immediately wound back up on rope pulley
16 by the spiral spring
46 so that a further pull on the handle
40 can take place soon. Of course, instead of spiral spring
46 there can also be used a torsion rod, a rubber band, or a coil spring as spring actuator
for winding rope
36 back up on rope pulley
16.
[0036] In Fig. 3 the pressure hose
77 is connected to a pressure storage container
82 which is fixedly attached to a bicycle
84. As a pressure storage container there can also be used the bicycle frame or a portion
thereof. The compressor
10 can be displaced by means of a swivel bracket
80 in such a manner that the friction roller
18 is brought into frictional engagement with bicycle tire
78. Because there is a risk of exceeding the nominal pressure of approximately 10 bar,
e.g. while traveling downhill with bicycle
84 in which the friction roller
18 of compressor
10 is in engagement with the bicycle tire
78, there is provided a pressure relief valve which can be incorporated into discharge
valve
32. Alternatively, the maximum compression and also the nominal pressure of the compressor
for a given air pressure can be set via adjustment of the dead space in cylinder
24 which dead space exists when the piston
22 is at its upper dead center. By means of the adjusting screw thread
23 between cylinder
24 and cylinder head
26 the volume of the dead space can be changed and the nominal pressure of compressor
10 varied.
[0037] In place of friction roller
18 a spur gear can also be placed on overrunning clutch
56 which can, for example, be driven by a chain, analogously to a sprocket of a bicycle.
[0038] If an appropriate pressure relief valve and a correspondingly smaller dead space
is provided in the compressor, higher pressures of up to 200 bar can be achieved by
means of this compressor. Air at this pressure is used, for example, for pumping up
shells such as are used for air guns in sport shooting.
[0039] Instead of air, other gaseous fluids can also be compressed so that the compressor
described here can also be used as refrigerant compressor in a refrigeration plant.
[0040] Fig. 4 shows such a refrigeration plant, consisting of the above described compressor
10, which is used here as refrigerant compressor, and a condenser
90, a collecting vessel
92, an expansion valve
94 and an evaporator
96. The compressor
10 has no electric connection, but is driven by hand or by external machinery. If it
is driven manually until the evaporator in a well insulated refrigerated chamber has
reached a temperature below 0° Celsius, then goods can be stored in the refrigerated
chamber for at least 24 hours without again having to operate the compressor. Such
a small refrigeration plant with hand driven compressor is suitable for remote locations
where no electric connection is available, or also for use in automotive vehicles
or camping vehicles if the battery is to be saved.
1. Compressor (10) for gaseous fluids, especially air, having a displacement body (22)
driveable by a drive shaft (14) , the drive shaft (14) being permanently adapted to
be set into rotation optionally either periodically by means of a rope pulley (16)
connectable thereto via a first overrunning clutch (52) by pulling on a rope (36)
wound up thereon, or adapted to be set into continuous rotation by means of a disc
or wheel shaped rotating body (18) via a second overrunning clutch (56), the rope
pulley (16) and the rotating body (18) being mounted compactly side by side on the
drive shaft (14) and the drive shaft (14) being mounted in a crankcase (12) for the
compressor (10).
2. Compressor according to Claim 1 characterized in that the rope pulley (16) and the
crankcase (12) are connected to each other by means of a spring actuator (46).
3. Compressor according to Claim 2, characterized in that the spring actuator (46) is
a spiral spring, a first end (41) of which is connected to the rope pulley (16) and
a second end (43) is connected to the crankcase (12).
4. Compressor according to one of Claims 1 to 3, characterized in that the rotating body
(18) is a friction roller.
5. Compressor according to one of Claims 1 to 3, characterized in that the rotating body
(18) is a spur gear.
6. Compressor according to one of Claims 2 to 5, characterized by a holder (75) serving
to hold the compressor (10) in position.
7. Compressor according to one of Claims 1 to 6, characterized in that the free end (38)
of the rope (36) is connected to a handle (40).
8. Compressor according to one of Claims 1 to 7 for producing high pressure air, characterized
by small size and by an adjustable pressure limiting device located between the compressor
(10) and a compressed air consumer.
9. Compressor according to Claim 8, characterized in that a size-adjustable dead space
of the compressor (10) is provided as the pressure limiting device.
10. Compressor according to Claim 8 or 9, characterized in that an adjustable pressure
relief valve is provided as the pressure limiting device.
11. Compressor according to Claim 6, characterized in that the holding device is a swivel
device (80) for pivotably attaching the compressor (10) to a frame of a bicycle (84).
12. Compressor according to Claim 8 and 11 characterized in that the compressed air consumer
is a tire of the bicycle (84) or a compressed air storage container (82) attached
to the frame of the bicycle (84).
13. Use of a compressor according to one of Claims 1 to 7 as refrigerant compressor for
a refrigeration plant.