Information
-
Patent Grant
-
6463894
-
Patent Number
6,463,894
-
Date Filed
Tuesday, December 19, 200023 years ago
-
Date Issued
Tuesday, October 15, 200221 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Mancene; Gene
- Castro; Arnold
Agents
- Sidley Austin Brown & Wood, LLP
-
CPC
-
US Classifications
Field of Search
US
- 123 260
- 123 267
- 123 268
- 123 280
- 123 286
- 123 46 R
- 123 46 A
- 123 46 H
- 123 37
- 123 38
- 123 39
- 123 274
- 123 275
- 227 10
- 227 11
-
International Classifications
-
Abstract
An internal combustion-engined tool including a piston and a combustion chamber (1) for generating power for driving the piston and having a bottom (3) adapted to receive the piston plate (9), an end wall (17) located opposite the bottom (3), a movable wall (14) located between the bottom (3) and the end wall (17) and provided with an opening element (14a), a movable separation wall (18) located between the bottom (3) and the movable wall (14) and provided with a plurality of openings (38), and an arrangement (42, 43) for injecting fuel gas into a space formed between the end wall and the movable wall upon the movable wall (14) and the separation wall (18) being displaceable in a direction of the bottom (3) upon collapsing of the combustion chamber (1).
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a portable internal combustion-engined tool and a method of forming a gas mixture in the tool combustion chamber. In particular, the present invention relates to a setting tool for driving-in fastening elements.
2. Description of the Prior Art
A tool and a method, which are referred to above, are described in a German Publication No. 199 50 352. In the tool, the combustion chamber can be brought into a collapsible condition when chamber walls provided therein and limiting chamber sections are displaced in a direction toward the chamber bottom and lie one upon another, whereby an expandable space is formed in the combustion chamber which is located, in a direction of displacement of the limiting walls, behind the last displaceable wall.
The tool described in the German publication includes a piston having a piston plate, and a combustion chamber for generating power for driving the piston and having a bottom adapted to receive the piston plate, an end wall located opposite the bottom, a movable wall located between the bottom and the end wall and provided with a check valve, a movable separation wall located between the bottom and the movable wall and provided with a plurality of openings, with the movable wall and the separation wall being displaceable in a direction of the bottom upon collapsing of the combustion chamber. In the side wall of the combustion chamber, there is provided means for feeding fuel gas thereinto.
The fuel gas is fed during the expansion of the chamber sections and actually shortly before they reach their completely expanded condition. Immediately thereafter, ignition takes place. As a result, the fed fuel gas has little time for homogeneous or uniform distribution in the combustion chamber. When the fuel gas is fed in a liquified state, a danger exists that the fuel gas would not evaporate completely. In both cases, the operating efficiency of the tool is reduced.
Accordingly, an object of the present invention is to provide a tool and a method which would insure a homogeneous distribution of the fuel gas in the combustion chamber.
SUMMARY OF THE INVENTION
This and other objects of the present invention, which will become apparent hereinafter, are achieved by feeding fuel gas into the expandable space which is formed behind the movable wall when the movable wall is displaced in the direction toward the chamber bottom.
The fuel gas can be fed into the expandable space shortly after the combustion chamber starts to collapse, when the expandable space has not yet expanded completely, or upon the complete expansion of the expandable space.
According to a preferred embodiment of the present invention, a check valve is provided in the end wall of the combustion chamber for admitting fresh air thereinto. The fresh air is aspirated into the expandable space upon collapsing of the combustion chamber. The check valve in the end wall at the same time prevents leakage of the fuel gas outside.
The fuel gas can be injected in a liquified form, gaseous form, or an already available air-fuel gas mixture can be injected.
In the collapsible condition of the combustion chamber, in the rear portion of the chamber, i.e., in the expandable space, a fresh air is present. Simultaneously or shortly after the tool has been pressed against an object, in which a fastening element has to be driven in, the fuel gas is injected into the expandable space, and the chamber sections begin to expand as a result of displacement of the movable walls. The fuel gas is mixed with air only in the rear space and flows into the respective chamber sections through openings provided in the movable walls. At that, the gas flow is deflected to provide for a better intermixing of the air-fuel gas mixture. Upon the complete expansion of the chamber sections and the reduction of the rear space practically to zero, the entire air-fuel gas mixture is available in the combustion chamber section and, thus, can be ignited. As a result of good or homogeneous intermixing of the air-fuel gas mixture, the combustion is characterized by a high efficiency which leads to a high energy release. When a liquified fuel gas in injected, there is sufficient time available for its evaporation as the ignition does not take place shortly after the injection but only after the complete expansion of the chamber sections. This further contributes to the increased efficiency of the tool.
According to a preferred embodiment of the present invention, as discussed above, a check valve is provided in the combustion chamber end wall, so that a fresh air is always aspirated into the combustion chamber as it collapses.
When the combustion chamber collapses, the residual gases are expelled through a check valve provided in the combustion chamber bottom. A still further check valve is provided in the combustion chamber movable wall, which faces the stationary end wall. This check valve provides for flow of the air-fuel gas mixture from the rear space into the expandable chamber sections but prevents flow of the residual gases from the chamber sections into the rear space.
According to further development of the present invention, the separation wall has an upwardly extending lug provided at its free end with a shoulder. The movable wall has a hollow extension which surrounds the lug of the separation wall. Both the separation wall lug and the movable wall extension extend through the end plate. A seal is provided between the movable wall extension and the wall of the opening in the end wall, through which the lug and the extension extend, in order to prevent any leakage of the air-fuel gas mixture. The movable wall extension and the separation wall lug are provided to insure displacement of the separation wall upon displacement of the movable wall. The distance between the end surface of the extension and the lug shoulder defines the distance between the movable wall and the separation wall and thereby the size of the forechamber section.
The fuel gas feeding means can be connected with a single metering valve. The metering valve can be set for a large amount which improves the metering precision. A standard valve can be used as a metering valve, which reduces the cost of the tool. The metering valve can be connected with the combustion chamber by one or several feeding channels or conduits.
Means is provided to insure the injection of the fuel gas at the beginning of the setting process to provide sufficient time for the liquified gas to evaporate. Eventually, an electronic control can be used to prevent ignition before expiration of certain time.
The novel features of the present invention, which are considered as characteristic for the invention, are set forth in the appended claims. The invention itself, however, both as to its construction and its mode of operation, together with additional advantages and objects thereof, will be best understood form the following detailed description of preferred embodiments, when read with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The drawings show:
FIG.
1
. an axial cross-sectional view of a tool according to the present invention in a position in which the combustion chamber section just starts to expand and a liquified gas is injected into the rear portion of the combustion chamber;
FIG. 2. a
cross-sectional view similar to that of
FIG. 1
but with the combustion chamber sections expanded to a greater extent; and
FIG. 3. a
cross-sectional view similar to that of
FIGS. 1-2
but with completely expanded combustion chamber sections at a time point of ignition.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1
shows an axial cross-sectional view of an internal combustion-engined tool for driving in fastening elements according to the present invention in the region of its combustion chamber with internal space V in a completely expanded condition.
As shown in
FIG. 1
, the setting tool has a cylindrical combustion chamber
1
with a cylindrical wall
2
and an annular bottom
3
with a central opening
4
. A guide cylinder
5
, which has a cylindrical wall
6
and a bottom
7
, adjoins the opening
4
in the bottom
3
of the combustion chamber
1
. A piston
8
is displaceably arranged in the guide cylinder
5
. The piston
8
consists of a piston plate
9
facing the combustion chamber
1
and a piston rod
10
extending from the center of the piston plate
9
. The piston rod
10
projects through an opening
11
formed in the bottom
7
of the guide cylinder
5
.
FIG. 1
shows a non-operational position of the setting tool in which the piston
8
is in its rearward off-position. The side of the piston plate
9
adjacent to the bottom
3
of the combustion chamber
1
is located closely adjacent to the bottom
3
, with the piston rod
10
projecting only slightly beyond the bottom
7
of the guide cylinder
5
. For sealing the cylinder chambers on opposite sides of the piston plate
9
for each other, sealing rings
12
,
13
are provided on the outer circumference of the piston plate
9
.
Inside of the combustion chamber
1
, there is provided a cylindrical plate
14
further to be called a movable combustion chamber wall or movable wall. The movable wall
14
is displaceable in the longitudinal direction of the combustion chamber
1
. For separating the chambers on opposite sides of the movable wall
14
, an annular sealing is provided on the circumference of the movable wall. The movable wall
14
has a central opening
16
.
Between the movable wall
14
and the annular bottom
3
of the combustion chamber
1
, there is provided a separation plate
18
. The separation plate
18
likewise has a circular shape and an outer diameter corresponding to the inner diameter of the combustion chamber
1
. The side of the separation plate
18
adjacent to the movable wall
14
is provided with a cylindrical lug
19
that projects through the central opening
16
in the movable wall
14
.
In the central opening
16
of the movable wall
14
, there is provided a circumferential or annular sealing sealingly engaging the outer circumference of the cylindrical lug
19
. At its free end, the cylindrical lug
19
is provided with a shoulder
20
the outer diameter of which exceeds the inner diameter of the opening
16
of the movable wall
14
. The movable wall
14
has, at its side remote from the separation plate a hollow cylindrical extension
15
the inner diameter of which corresponds to the inner diameter of the opening
16
. The hollow cylindrical extension
15
is coaxial with the opening
16
and concentrically surrounds the lug
19
. The free end of the extension
15
is spaced a predetermined distance from the annular shoulder
20
. The lengths of both the cylindrical lug
19
and the cylindrical extension
15
of the movable wall
14
are so selected that they extends through an end wall
17
of the combustion chamber
1
, which closes the combustion chamber
1
at its side remote from the piston
8
, in any position of the movable wall
14
. Both the cylindrical extension
15
and the cylindrical lug
19
project through the opening
17
a
in the end wall
17
. An annular seal
17
b
, which is provided in the wall of the opening
17
a
, sealingly engages the extension
15
. The seal
17
b
prevents leakage of fuel gas from the combustion chamber
1
outside through the opening
17
a.
In the end wall
17
, there is provided a check valve
17
c
that permits only flow of air into the combustion chamber
1
but prevents any flow from the combustion chamber. Another check valve
14
a
is provided in the movable wall
14
. The check valve
14
a
enables flow only in a direction toward the separation plate
18
but not in the opposite direction. The separation plate
18
has a plurality of through openings
38
arranged along a concentric path at the same distance form the axis of the combustion chamber
1
. A third check valve
31
is provided in the bottom
3
of the combustion chamber
1
. The check valve
31
provides for gas flow form the combustion chamber
1
outside but prevents any flow in opposite direction.
For displacing the movable wall
14
, there are provided several, e.g., three drive rods
23
uniformly distributed along the circumference of the movable wall
14
and fixedly connected therewith. Only one of the drive rods
23
is shown in FIG.
1
. The drive rods
23
extend parallel to the axis of the combustion chamber
1
and outside of the cylindrical wall
6
of the guide cylinder
5
. The drive rods
23
extend through openings
24
, respectively, formed in the separation plate
18
and through corresponding openings
25
formed in the bottom
3
of the combustion chamber
1
. Each of the openings
25
is provided win a circumferential seal located in the surface defining the opening
25
for sealing the combustion chamber
1
from outside. The movable wall
14
is connected with drive rods
23
by, e.g., screws
27
which extend through the movable wall
14
and are screwed into the drive rods
23
. The free ends of the drive rods
23
are connected with each other by a drive ring
28
which is arranged concentrically with the combustion chamber axis and which circumscribes the guide cylinder
5
. The drive ring
28
is connected with the drive rods
23
by screws which extend through the drive ring
28
and are screwed into the drive rods
23
through end surfaces of the free ends of respective drive rods
23
. Each of the drive rods
23
supports a compression spring
30
extending between the bottom
3
of the combustion chamber
1
and the drive ring
28
. The compression springs
30
are designed for pulling the movable wall
14
toward the bottom
3
.
The drive ring
28
is provided, in its region beneath the check valve
31
, with a stop
32
which prevents opening of the check valve
31
in a position of the movable wall
14
in which it is spaced from the bottom
3
of the combustion chamber
1
by a greatest distance and is in its locking position. The locking position of the movable wall
14
is defined by a locking position of the drive ring
28
when the drive ring is displaced into a predetermined end position thereof upon the tool being pressed against an object. In this position, the stop
32
blocks the checking valve
31
, preventing its opening. Thus, upon the tool being pressed against an object, the drive ring
28
is displaced toward the bottom
3
of the combustion chamber
1
, and the drive rods
23
displace the movable combustion chamber wall
14
toward the end wall
17
. After the movable wall
14
travels a certain distance, the. hollow cylindrical extension
15
abuts from beneath the annular shoulder
20
, and the separation plate
18
is carried with the movable wall
14
. This position of the combustion chamber wall
14
and the separation plate
18
is shown in FIG.
2
. In this position, there are formed a forechamber section
21
between the movable wall
14
and the separation plate
18
and a main chamber section
22
between the separation plate
18
and the combustion chamber bottom
3
. The space V between the end wall
17
and the movable wall
14
is reduced. The movable wall
14
and the separation plate
18
are displaced until the movable wall
14
reaches its locking position which is defined by the locking position of the drive ring
28
. This position is shown in FIG.
3
. In this position, the movable wall
14
abuts the end wall
17
. The forechamber section
21
and the main chamber section
22
are expanded to their maximum possible extend, and the space V between the movable wall
14
and the end wall
17
is reduced practically to zero.
At the lower end of the guide cylinder
5
, there are provided openings
39
for letting air out of the guide cylinder
5
upon movement of the piston
8
toward the guide cylinder bottom
7
. At the lower end of the guide cylinder
5
, there is also provided damping means
40
for damping the movement of the piston
8
. As soon as the piston
8
passes the openings
39
, the waste gases are expelled from the guide cylinder
5
through the openings
39
.
The cylindrical wall
2
of the combustion chamber
1
has, in the vicinity of the combustion chamber end wall
17
, a radial opening
41
. The opening
41
communicates via a feed channel
43
with a metering head
45
having a metering valve, not shown. A liquefied gas is delivered to the metering head
45
from a flask
46
. The liquefied gas flows from the metering head
45
through the feed channel
43
into the opening
41
when the metering head
45
is pressed toward the cylindrical wall
2
of the combustion chamber
1
. The cross-section of the radial opening
41
is reduced in a direction toward the combustion chamber
1
, with the transitional surface serving as a stop for the feed channel
43
. The pressing of the metering head
45
toward the cylindrical wall
2
is effected with a stirrup
47
which is pivotally supported on the cylindrical wall
2
at a pivot point
48
. A free end of the cylindrical extension
15
engages the end
49
of the stirrup
47
when the movable wall
14
moves in a direction toward the end wall
17
. The cylindrical extension
15
lifts the end
49
, pivoting the stirrup
47
in the counterclockwise direction about the pivot point
48
. Upon pivotal movement of the stirrup
47
, the other end
50
thereof presses the metering head
45
toward the cylindrical wall
2
. This process starts already at the beginning of the movable wall
14
. The metering head
45
and the flask
46
form a unitary assembly and are permanently connected with each other. The system metering head
45
-flask
46
can, e.g., can be titled about an axle provided in the bottom region of the flask
46
.
As discussed above,
FIG. 3
shows a completely expanded condition of the combustion chamber
1
, i.e., with the forechamber section
21
and the main chamber section
22
being completely expanded and the space V reduced practically to zero. The feed channel or conduit
43
is pressed toward the cylindrical wall
2
, and the metering valve is open, discharging its content into the forechamber section
21
. The movable plate
14
is in its locked position, and the check valve is blocked by the stop
32
. The tool is ready for ignition.
To provide for ignition, the cylindrical lug
19
is formed, in its region adjacent to the separation plate
18
, as an ignition cage
51
in which an ignition section
21
. The ignition element
52
is located in the central region of the ignition cage
51
which is provided with a plurality of circumferential openings
53
through which a laminar flame front can exit from the ignition cage
51
into the forechamber section
21
. The openings
53
can, e.g., be uniformly distributed over the circumference of the cylindrical lug
19
. They become free when the movable wall
14
is displaced with respect to the separation plate
18
, at the start of the process, so that it engages from beneath the annular shoulder
20
of the lug
19
.
Below, the operation of the setting tool, shown in
FIGS. 1-2
, will be described in detail.
FIG. 1
shows the condition of the combustion chamber
1
in the off position of the setting tool. The combustion chamber
1
is completely collapsed, with the separation plate lying on the bottom
3
of the combustion chamber
1
and the movable wall
14
lying on the separation plate
18
. In order to distinguish the wall
14
and the plate
18
, for the clarity sake, they are shown slightly separated. The piston
8
is in its rearward off-position so that practically no space remains between the piston
8
and the separation plate
18
if one would disregard a small clearance therebetween. The position, in which the movable wall
14
lies on the separation plate
18
, results from the compressing spring
30
biasing the drive ring
28
away from the bottom
3
, and the ring
28
pulls with it the movable wall
14
via the drive rods
23
. In this position, the drive ring
28
and the stop
32
are spaced from the check valve, so that the check valve
32
remains closed. The system metering head
45
-flask
46
is pivoted away from the wall
2
of the combustion chamber
1
, with the metering valve being closed.
When in this condition, the setting tool is pressed with its front point against an object, the fastening element should be driven in, a mechanism, not shown, applies pressure to the drive ring
28
displacing it in the direction of the bottom
3
of the combustion chamber
1
. This takes place simultaneously with the setting tool being pressed against the object. Upon displacement of the drive ring
28
toward the bottom
3
, the movable wall.
14
is lifted of the separation plate
18
with the cylindrical extension
15
displacing together with the movable wall
14
. The free end of the extension
15
engages the end
49
of the stirrup
47
, pivoting the stirrup
47
counterclockwise about the pivot point
48
, so that the other end
50
of the stirrup
47
presses the metering head
45
toward the combustion chamber wall
2
. The feed channel
43
is pressed into the opening
42
, and is displaced inward, opening the metering valve. This leads to the injection of the liquefied fuel gas into the space V of the combustion chamber
1
. Thus, the injection of the fuel gas into the space V takes place already at an early stage of the process, after the start of the displacement of the movable wall
14
.
Upon further displacement of the movable wall
14
in a direction toward the end wall
17
, the check valves
17
c
and
31
remain closed, while the check valve
14
a
is open. The air-fuel gas mixture, thus, can flow from the space V between the end wall
17
and the movable wall
14
into the forechamber section
21
between the movable wall
14
and the separation plate
18
through the check valve
14
a.
Upon further displacement of the movable wall
14
in a direction toward the end wall
17
, the end of the cylindrical extension
15
engages from beneath the shoulder
20
of the lug
19
, lifting the lug
19
, together with the separation plate
18
, whereby the separation plate
18
is lifted from the bottom
3
. Now, the air-fuel gas mixture can flow through the opening
38
in the separation plate
18
into the main chamber section
22
which starts to expand. At this point in time, the forechamber section
21
is already in its completely expanded condition. This position is shown in FIG.
2
.
From this point in time, the movable wall
14
is displaced together with separation wall
18
until the movable wall
14
abuts the end wall
17
and the drive ring
28
becomes locked. The further displacement of the movable wall
14
is, thus, blocked. In this position, the main chamber section
22
is also in its completely expanded condition, and the space between the movable wall
14
and the end wall
17
is reduced practically to zero. As a result of movement of the movable wall
14
and the separation plate
18
, the initially injected in the combustion chamber, liquefied fuel gas, upon penetrating through the check valve
14
a
and the openings
38
into the forechamber section
21
and the main chamber
22
, respectively, is mixed up further, so that soon in the entire combustion chamber
1
, in both chambers sections
21
,
22
, a homogeneous air-fuel gas mixture becomes available. This condition of the combustion chamber is shown, as discussed, in FIG.
3
. The feed channel
43
extends into the radial opening
41
, and the metering valve is open. This, however, is of no consequences, as the metering valve is empty and its inlet is closed. The check valve
31
is closed by the stop
32
that prevents the check valve
31
from opening.
Upon actuation of a pull lever, a trigger, or the like of the tool, an ignition process is initiated, with the movable wall
14
, the separation plate
18
, and the drive ring
28
being locked in their positions. Shortly thereafter, ignition, spark is generated by the actuation of the ignition element
52
inside the cage
51
. A mixture of air and the fuel gas, which was formed in each of the chamber sections
21
and
22
, is ignited. First, the mixture starts to burn aminary in the forechamber
21
, and the flame front spreads with a relatively low speed in a direction of the openings
38
. No gas can flow back through the check valve
14
a
. It is closed. The unconsumed air-fuel gas mixture is displaced ahead and enters, through the openings
38
, the main chamber section
22
, creating there turbulence and pre-compression. When the flame front reaches the openings
38
; it enters the main chamber section
22
, due to the reduced cross-section of the openings
38
, in the form of flame jets, creating there a further turbulence. The thoroughly mixed, turbulent air-fuel gas mixture in the main chamber section
22
is ignited over the entire surface of the flame jets. It bums with a high speed which significally increases the combustion efficiency.
The combustible mixture impacts the piston
8
, which moves with a high speed toward the bottom
7
of the guide cylinder
5
, forcing the air from the guide cylinder
5
out through the openings
39
. Upon the piston plate
9
passing the openings
39
, the exhaust gas is discharged therethrough. The piston rod
10
effects setting of the fastening element. After setting or following the combustion of the air-fuel gas mixture, the piston
8
is brought to its initial position, which is shown in
FIG. 3
, as a result of thermal feedback produced by cooling of the flue gases which remain in the combustion chamber
1
and the guide cylinder
5
. As a result of cooling of the flue gases, an underpressure is created behind the piston
8
which provides for return of the piston
8
to its initial position. The combustion chamber
1
should remain sealed until the piston
8
reaches its initial position.
After return of the piston
8
to its initial position, the movable wall
14
and the separation plate
18
are unlocked. The compression springs
30
bias the drive ring
28
away from the bottom
3
of the combustion chamber
1
, and the drive ring
28
, together with the stop
32
, move downward, with the stop
32
releasing the check valve
31
. Upon further displacement, the drive ring
28
pulls, via the drive rods
23
, the movable wall
14
in a direction toward the bottom
3
. Later, the separation plate
18
is displaced downwardly, by the movable wall
14
which abuts the separation plate
18
. Upon movement of the movable wall
14
and the separation plate
18
toward the bottom
3
, the exhaust gases in the forechamber section
21
are pushed through the openings
38
in the separation plate
18
into the main chamber
22
and therefrom, together with the exhaust gases formed in the main chamber
22
, through the open check valve
31
outside. The check valve
14
a
is closed during this movement. At the same time, the space V between the movable wall
14
and the end wall
17
begins to expand. This results in opening of the check valve
17
c
and to the flow of the fresh air into the combustion chamber
1
, i.e., into the space V between the end wall
17
and the movable wall
14
. Finally, the separation plate
18
abuts the bottom
3
, lying thereon, with the movable wall
14
lying on the separation plate
18
. Thus, the combustion chamber
1
has completely collapsed and become free of waste gases, with the entire expanded space V between the end wall
17
and the movable wall being filled with the fresh air. Meanwhile, the stirrup
47
pivots away from the metering head
45
, being released as a result of movement of the cylindrical extension
15
, together with movable wall
14
downwardly. This results in the movement of the feed channel
43
out of the metering head, whereby the outlet of the metering valve in the metering head
45
becomes closed, opening the inlet valve. The liquefied gas can now flow from the flask
46
into the metering valve, filling it with the fuel gas. The process can now be started again, accompanied by the injection of the fuel gas and formation of a homogeneous air-fuel gas mixture.
Though the present invention was shown and described with references to the preferred embodiments, such are merely illustrative of the present invention and are not to be construed as a limitation thereof and various modifications of the present invention will be apparent to those skilled in the art. It is therefore not intended that the present invention be limited to the disclosed embodiments or details thereof, and the present invention includes all variations and/or alternative embodiments within the spirit and scope of the present invention as defined by the appended claims.
Claims
- 1. An internal combustion-engined tool, comprising a piston having a piston plate (9); and a combustion chamber (1) for generating power for driving the piston and having a fixed bottom (3) adapted to receive the piston plate (9), an end wall (17) located opposite the fixed bottom (3), a movable wall (14) located between the fixed bottom (3) and the end wall (17) and provided with a check valve (14a), a movable separation wall (18) located between the fixed bottom (3) and the movable wall (14) and provided with a plurality of openings (38), the movable wall (14) and the separation wall (18) being displaceable in a direction of the fixed bottom (3) upon collapsing of the combustion chamber (1) with formation of an expandable space (V) between the movable wall (14) and the end wall (17) during displacement of the movable wall (14) in the direction toward the fixed bottom (3), and means for feeding fuel gas into the expandable space (V).
- 2. A tool according to claim 1, further comprising at least one further check valve (17c) provided in the end wall (17).
- 3. A tool according to claim 1, wherein the separation plate (18) has a lug (19) provided, at a free end thereof with a shoulder (20), and wherein the movable wall (14) has a hollow extension (15) surrounding the lug (19), with both the lug (19) and the extension (15) extending through the end wall (17).
- 4. A tool according to claim 1, wherein the feeding means comprises single metering means.
- 5. A method of providing a combustible gas mixture in a combustion chamber of an internal combustion-engined tool and having movable walls (14, 18) limiting two chamber sections (21, 22) and provided with openings (14a, 38) therethrough, the method comprising the steps of displacing the movable walls (14, 18) in a direction toward a combustion chamber bottom (3), whereby a combustion chamber space (V) lying between an end wall (17) of the combustion chamber (1) opposite the bottom (3) and a movable wall (14) facing the end wall (17) expands; feeding the fuel gas into the combustion chamber space (V); and feeding fresh air through the end wall (17) of the combustion chamber located opposite the combustion chamber bottom (3) during displacement of the movable walls (14, 18) in the direction toward the bottom (3).
- 6. A method of providing a combustible gas mixture in a combustion chamber of an internal combustion-engined tool and having movable walls (14, 18) limiting two chamber sections (21, 22) and provided with openings (14a, 38) therethrough, the method comprising the steps of displacing the movable walls (14, 18) in a direction toward a combustion chamber bottom (3), whereby a combustion chamber space (V) lying between an end wall (17) of the combustion chamber (1) opposite the bottom (3) and a movable wall (14) facing the end wall (17) expands; feeding the fuel gas into the combustion chamber space (V); and expanding the chamber sections (21, 22) during which step the fuel gas flows from the space (V) behind the movable wall 14 into the chamber sections (21, 22).
- 7. A method according to claim 6, comprising the step of igniting the fuel gas after collapse of the space (V) behind the movable walls (14, 18) resulting from expansion of the chamber sections (21, 22).
- 8. A method of providing a combustible gas mixture in a combustion chamber of an internal combustion-engined tool and having a fixed bottom (3) and movable walls (14, 18) limiting two chamber sections (21, 22) and provided with openings (14a, 38) therethrough, the method comprising the steps of displacing the movable walls (14, 18) in a direction toward the fixed bottom (3), upon collapsing of the combustion chamber, whereby a combustion chamber space (V) lying between an end wall (17) of the combustion chamber (1) opposite the bottom (3) and a movable wall (14) facing the end wall (17) expands; and feeding the fuel gas into the expanded combustion chamber space (V).
- 9. A method according to claim 8, wherein the feeding step includes feeding the fuel gas in a liquefied form.
Priority Claims (1)
Number |
Date |
Country |
Kind |
199 62 597 |
Dec 1999 |
DE |
|
US Referenced Citations (2)
Number |
Name |
Date |
Kind |
5213247 |
Gschwend et al. |
May 1993 |
A |
6041603 |
Phillips |
Mar 2000 |
A |