JPS63130497A - Ship propeller - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to marine propulsion devices, such as outboard motors and stern drive units, with power steering systems.

Prior Art Attention is drawn to the following US patents which disclose power steering systems for marine propulsion systems: US Pat.

Patent Holder Patent Number Issue Date Covert
4,399,734 1983, 8.23 Piras 3,045,434 1962. 7.2
4 Konishi et al. 4,043,123 1977,
8.23 Takahashi et al. 4,193.264 19
80.3.18 Stelzer 2,967.392
1961.1.10 May 2
．． 906,292 L959.9.29 Prayer 2,910,327 1959. IQ, 2
7 Hamotsuku 2,939.417 19e0.
6. 7 Simancas 3,631.833 1
972. 1.4 Polst 3,774.56
8 1973.1.27 Kotkus et al. 4,227
．． 481 1980.10.14 Polst 4
,295.833 1981.10.20 Hall et al.
4,373,920 1983.2.15 Porst 4,419,084 1983.12.
6 Ferguson 4,449,945 1984.
5.22 holes 4,568.292 19
Also of note is U.S. Pat.

Summary of the Invention The present invention provides a propulsion unit having a rotatably mounted propeller, an engine coupled to and driven by the propeller, a member movable with respect to the propulsion unit,
A marine vessel propulsion system is provided comprising operator actuated pneumatic means for selectively creating relative movement between the propulsion unit and the members.

In one embodiment, the pneumatic means operates in relation to a reference pressure, and the propulsion device further comprises a source of a pressure different from the reference pressure, the pressure source being coupled to the pneumatic means. .

In one embodiment, the pressure source provides a pressure higher than the reference pressure, and the marine propulsion system further includes an accumulator coupled to the pneumatic means and allows gas to flow from the pressure source to the accumulator, and the marine propulsion device further includes an accumulator coupled to the pneumatic means, allowing gas flow from the pressure source to the accumulator, and providing a pressure supply from the accumulator. and a check valve to prevent the flow of gas to the source.

In one embodiment, the pressure source provides a pressure lower than the reference pressure, and the marine propulsion system further includes an accumulator coupled to the pneumatic means and allowing gas to flow from the accumulator to the pressure source, and the marine propulsion device further includes an accumulator coupled to the pneumatic means and allowing gas to flow from the accumulator to the pressure source. It is equipped with a check valve that prevents the flow of gas to.

In one embodiment, the engine further includes a crankcase, and the pressure source includes the crankcase.

In one embodiment, the engine further includes a combustion chamber;
A pressure source includes the combustion chamber.

In one embodiment, the pneumatic means includes a cylinder, a piston slidably arranged within the cylinder and dividing the cylinder into opposing chambers, and a piston arranged slidably within the cylinder to control the flow of gas into the cylinder. a pulp assembly in communication with the chamber, and one of a cylinder and a piston connected to the movable member.

In one embodiment, the other of the cylinder and the piston is fixed against movement in the axial direction of the cylinder, the one of the cylinder and the piston is movable in the axial direction of the cylinder, and the pulp assembly is fixed in the axial direction of the cylinder. a pulp housing communicating with the opposing chambers and a valve member movable relative to the pulp housing to control gas flow to the cylinder, one of the pulp housing and the valve member being connected to the cylinder; The piston is connected to said one of the pistons so as to move therewith.

In one embodiment, the pneumatic means further connects the other of the valve housing and the valve member to the one of the pulp housing and the valve member.

and operator-actuated means for selectively moving the actuator.

In one embodiment, the propulsion unit includes a transmission coupling the engine to the propeller, and the movement of said member relative to the propulsion unit controls the transmission.

In one embodiment, the engine includes a throttle, and the position of the member relative to the propulsion unit controls the throttle.

In one embodiment, the member is a mounting placket adapted to be fixedly mounted on the ground of the ship's hull, and the propulsion unit is pivoted about a steering axis substantially perpendicular to the mounting placket. so that the pneumatic means produce a steering movement of the propulsion unit.

The invention also provides a device comprising an engine with a combustion chamber, a movable member and pneumatic means for moving the member, the pneumatic means being in communication with the combustion chamber.

The invention further provides an engine having a crankcase subjected to periodic conditions of relatively high and low pressures;
An apparatus is provided, comprising a movable member and pneumatic means, the pneumatic means communicating with a crankcase.

The main feature of the invention is the provision of a marine vessel propulsion system with pneumatic power assist means for moving the throttle lever or shift lever or for steering the propulsion unit.

Another principal feature of the invention is the use of the engine crankcase or combustion chamber as the pressure source for the pneumatic power assist.

This allows the pump to be driven by an engine, etc.
No additional pressure source is required. The cost of providing power assistance is therefore reduced.

The drawings show a marine propulsion system +tlO embodying the present invention. As shown in FIG. 1, the ship propulsion device 1
0 includes a mounting assembly mounted on the hull dyeing 12. Although a variety of flexible mounting assemblies can be used, in the illustrated construction the mounting assembly includes a ground dyeing placket 14 fixedly mounted above the ground dyeing 12;
It includes a swivel bracket mounted on the ground dyeing plaque 14 for rotational movement about a tilt axis 18 that is substantially horizontal thereto.

The marine propulsion device 10 is further mounted on the swivel bracket 16 for rotation therewith about a generally horizontal steering axis 220 and for rotation with the swivel bracket about a tilt axis 18. Promotion Unino) 2
Contains 0. Propulsion unit 20 includes a rotatably mounted propeller 24 and an engine 26 drivingly coupled to propeller 24 by a conventional drive train including a transmission 28 .

In the illustrated configuration, engine 26 is a two-stroke internal combustion engine that includes a throttle 30, a crankcase 32, and a pair of cylinders each having a combustion chamber 34 (see FIG. 3). It will be appreciated that the invention is also applicable to 4-cycle engines.

The marine propulsion system 10 further includes a steering arm 36 (see FIG. 1.4) that is rigidly coupled to the propulsion unit 20 to effect steering movement relative to the propulsion unit 200 swivel placket 16 and is movably mounted to the propulsion unit 20. a shift lever or shift member 38 (FIG. 2) which is operatively coupled to the transmission 28 to control the transmission 28;
It includes a throttle control lever member 40 (FIG. 3) movably mounted on the propulsion unit 7 and operably connected to the throttle 30 to control the throttle. Such configurations are known in the art and require no more detailed explanation.

The marine propulsion system 10 further includes operator actuated pneumatic means 42 (see FIG. 2) for selectively effecting relative movement between the propulsion unit 20 and the shift member 38.
Contains. While any suitable pneumatic means may be employed, the pneumatic means 42 in this embodiment may include a cylinder 44, a cylinder 44, and a cylinder 44 slidably mounted within the cylinder 44, connecting the cylinder 44 to an opposing upper and lower chamber. chamber 48
．． The piston 46 is divided into 50 parts. The pneumatic means 42 further comprises a piston rod 52 having one end rigidly connected to the piston 46 and an opposite end rigidly connected to the propulsion unit 20.

Therefore, the piston 46 is fixed against movement in the axial direction of the cylinder 44. On the other hand, the cylinder 44 is
It is movable relative to the piston 46 in the axial direction of the cylinder 44, and is connected to the shift member 38 so as to move integrally therewith. It will be appreciated that in other embodiments, cylinder 44 may be fixed and piston 46 coupled to shift member 38.

Pneumatic means 42 further includes a pulp assembly 53 communicating with a chamber opposite cylinder 440 for controlling the flow of nocus into cylinder 44 . Although a variety of suitable pulp assemblies may be employed, in the illustrated configuration the valve assembly 53 is movable with respect to the pulp housing 54 that communicates with the opposing puncher of the cylinder 44 and A pulp member 56 is included to control gas flow to 44. In this embodiment, the pulp housing 54 is coupled to and moves with the cylinder 44. In other embodiments, pulp member 56 may be coupled to cylinder 44 for movement therewith.

As shown in FIG. 2, pulp assembly 53 is a conventional spool pulp assembly.

The pulp housing 54 has a generally cylindrical hole or cavity 58 in its shell 2, in which the valve element or spool 56 is positioned in a first or upper position, a second or lower position, and It is arranged for axial movement to and from a third central position (shown in FIG. 2). Fluid or gas may enter and exit cavity 58 through any of three boats 60, 62, 64 spaced axially along pulp housing 54. Boat 62 is subjected to a reference pressure, preferably atmospheric pressure. In the illustrated configuration, the boat 62 is communicated to the atmosphere by a check valve 78 that connects the boat 62 to the atmosphere.
Allow gas to flow from 2 to the atmosphere 7, from the atmosphere to the boat 6
The flow of gas to 2 is prevented. The pulp housing 54 further includes boats 66 and 68 which are disposed opposite the upper port 600 and communicate with the lower cylinder chamber 50 via a passageway 70, and then generally opposite the lower port 64. Boats 72 and 74 are arranged and communicated with the upper cylinder chamber 48 via a passage 76.

The pulp member or spool 56 includes a pair of axially spaced and enlarged cylindrical portions or lands 80 and 82 that extend inside the cavity 58 during axial movement of the spool 56. Slidably and sealingly engages the wall. When spool 56 is in the center position as shown in FIG.
, and the lower land 82 closes the lower ports 64 and 74. At the same time, both ports 68 and 72
communicates with port 62 through passageways 70 and 76.
The cylinder chambers 50 and 48 are connected to each other through the cylinder chambers 50 and 48, respectively.

The pulp member or spool 56 further includes shoulder means 84 for mechanically coupling the pulp member 56 to the pulp housing 54, which abuts the ends of the pulp housing 54 and when the pneumatic means 42 is turned off, the pulp member 56.

The ship propulsion device 10 further includes a pressure supply source different from the reference pressure (atmospheric pressure). Preferably, the pressure source is at a pressure above atmospheric pressure. Although any suitable pressure source may be employed, in the illustrated configuration the pressure source includes one of the combustion chambers 34 of the engine 26. In other embodiments, as shown in dotted lines in FIG.
The pressure source may include the crankcase 32 rather than the combustion chamber 34.

Marine propulsion system 10 further includes an accumulator 86 communicating between combustion chamber 34 and pulp housing 54 . More specifically, accumulator 86 communicates with ports 60 and 64 via conduits 94 and 96, respectively, and with combustion chamber 34 via conduit 88. Preferably, the conduit 88 is connected to the combustion chamber 3 at or near the head of the cylinder to maximize the pressure that the conduit 88 experiences.
It connects to 4. Conduit 88 allows gas to flow from combustion chamber 34 to accumulator 86 .
6 to the combustion chamber 34 is provided with a check valve 9q that prevents the flow of gas from the combustion chamber 34. A valve 92 is provided to drain residue from the accumulator 86.

As is known in the art, fuel chamber 34 is subject to periodically varying high and low pressure conditions. Check valve 90 allows gas flow from combustion chamber 34 to accumulator 86 during high pressure conditions and prevents gas flow from accumulator 86 to combustion chamber 34 during low pressure conditions. Therefore, the accumulator 86 is filled with high pressure gas.

With valve member 56 in the central position as shown in FIG. 2, upper land 80 closes port 60 and lower land 82 closes port 64, so that accumulator 86 is in communication only with combustion chamber 34. The combustion chamber 34 is then filled with gas at a pressure equal to the pressure within the combustion chamber 34. Once the pressure within the accumulator 86 reaches the pressure within the combustion chamber, there is no pressure loss from the combustion chamber 34 through the conduit 88.

Therefore, communication of the accumulator 86 with the combustion chamber 34 has no effect on the operation of the engine 26, except when the pressure in the accumulator 86 is reduced by the operation of the pneumatic means 42.

As is clear from Figure 2, Varpuno Uzing 5
By moving the valve member 56 to the upper position with respect to 4, the accumulator 86 communicates with the upper cylinder chamber 48 via the port 64, the port 74, and the passage 76,
The lower cylinder chamber 50 has a passage 70. It communicates with atmospheric pressure via ports 68 and 62. At the same time, lower land 82 closes port 72 and upper land 80 closes ports 60 and 66. 7 Therefore,
The high pressure in the upper cylinder chamber 48 causes the cylinder 44 to move upwardly relative to the piston 46, which causes the shift member 38 to move upwardly relative to the propulsion unit 20. The upward movement of the cylinder 44 also causes the upward movement of the pulp housing 54 relative to the valve member 56? occurs, which causes the pulp member 56 to return to its central position relative to the pulp housing 54.

Conversely, when pulp member 56 moves to a lower position relative to pulp housing 54, accumulator 86 moves toward port 60.
, port 66 and passageway 70 to lower cylinder chamber 50, and upper cylinder chamber 48 communicates with the atmosphere through passageway 76, port 72 and port 62. Additionally, upper land 80 closes port 68 and lower land 82
closes ports 64 and 74. The high pressure within the lower cylinder chamber 50 causes the cylinder 44 to move downwardly relative to the piston, which causes the shift member 38 to move downwardly. The downward movement of the cylinder 44 further moves the pulp housing 54 downwardly relative to the pulp member 56 , thereby returning the pulp member 56 to its central position relative to the pulp housing 54 .

The pneumatic means 42 further includes operator actuated means for selectively moving the pulp member 56 relative to the pulp housing 54.

In this embodiment 2, the means for moving comprises a remotely located shift actuator 98 coupled to the pulp member 56 by a conventional push-and-pull cable 100.

As shown in FIG. 3, marine propulsion system 10 further includes operator actuated pneumatic means 102 for selectively creating relative movement between propulsion unit 20 and throttle member 40. As shown in FIG. In this embodiment, the pneumatic means 102 is similar to the pneumatic means 42 (see FIG. 3) and is slidably connected to the cylinder 104.
A piston 106 is disposed within the cylinder 104 and divides the cylinder 104 into opposing upper and lower chambers 108 and 110. Pneumatic means 102 further includes a piston rod 112 having one end firmly coupled to piston 106 and an opposite end coupled to throttle member 40 . The cylinder 104, on the other hand, is rigidly connected to the propulsion unit 20 and is thus fixed against movement in the axial direction of the cylinder 104.

Pneumatic means 102 further comprises a pulp assembly 103 similar to pulp assembly 53 of pneumatic means 42 . Pulp assembly 103 includes a pulp housing 114 communicating with opposing chambers of cylinder 104 and a pulp member 116 movable relative to pulp housing 114 to control gas flow to cylinder 104. . Pulp housing 114 is movable relative to cylinder 104 and is coupled to throttle member 40 and piston rod 112 for movement therewith.

The pulp housing 114 has a generally cylindrical hole or cavity 118 therein in which the pulp member 116 is positioned in a first or upper position, a second or lower position, and a third'f or lower position. Center position (shown in Figure 3)
It is arranged to move axially between. Fluid or gas may enter or exit cavity 118 through any of three ports 120, 122, and 124 spaced axially along pulp housing 114.

Port 122 is communicated to the atmosphere by a check valve 125 that allows gas to flow from the atmosphere to port 122 and prevents gas from flowing from port 122 to the atmosphere.

The pulp housing 114 is further positioned generally opposite the upper boat 120 and includes a flexible conduit or passageway 13.
ports 126 and 128 that communicate with the lower cylinder chamber 110 via a flexible conduit or passageway 136 located generally opposite the lower port 124 and the Connecting ports 132 and 13
It is equipped with 4.

The pulp member 116 has a pair of axially spaced enlarged cylindrical portions or lands 140 and 142 that slide against the interior wall of the cavity 118 during axial movement of the spool 116. possible and sealing engagement. When spool 116 is in the center position as shown in FIG. 3, upper land 140 closes upper ports 120 and 126 and lower land 142 closes lower ports 124 and 134. At the same time, ports 128 and 132 both communicate with port 122 via cavity 118 and each have passageway 1.
It communicates with the cylinder chambers 110 and 108 via 30 and 136.

The marine propulsion system 10 further includes a reference pressure or subatmospheric pressure source. In the illustrated configuration, the pressure source includes a crankcase 32 of engine 26.

The marine propulsion system 10 further includes a check valve 146 and an accumulator 148 in communication with the crankcase 32 and ports 120,124. Check pulp 146 is
Gas is allowed to flow from the accumulator 148 to the crankcase 32t, but gas is prevented from flowing from the crankcase 32t to the accumulator 148. As is understood in the art, the crankcase 32 is relatively high and will be subject to periodic conditions of low pressure.

Check valve 146 closes accumulator 148 during low pressure conditions.
during high pressure conditions, allowing gas flow from the crankcase 32 to the accumulator 14.
Block the flow to 8.

Pneumatic means 102 further includes operator actuated means for selectively moving pulp member 116 relative to pulp housing 114. Although various suitable means may be used, in the illustrated configuration the means include a remotely located throttle actuator 150 coupled to the pulp member by a conventional push-pull type cable 152.

The operation of pneumatic means 102 is similar to the operation of pneumatic means 42. Pulp member 1 relative to pulp housing 114
16 causes the accumulator 148 to communicate with the upper cylinder chamber 108 and the lower cylinder chamber 110.
communicates with the atmosphere.

Therefore, the lower pressure in the upper cylinder chamber 108 causes the piston 106 to move upwardly relative to the cylinder 104.
, whereby the throttle member 4o moves upward with respect to the propulsion unit 20. The upward movement of piston 106 further causes upward movement of pulp housing 114 relative to the pulp member, which returns pulp member 116 to its original position relative to pulp housing 114.

Conversely, the pulp member 11 relative to the pulp housing 114
6 moves downward, the accumulator 148 communicates with the lower cylinder chamber 110, and the upper cylinder chamber 108 communicates with the atmosphere. The low pressure in the lower cylinder chamber 110 causes the piston 106 to move downwardly relative to the cylinder 104, thereby moving the squirrel member 40 downwardly. The downward movement of piston 106 also causes downward movement of pulp housing 114 relative to pulp member 116, which returns pulp member 116 to its original position relative to pulp housing 114.

The marine propulsion system 10 further includes operator actuated pneumatic means 154 for selectively effecting relative movement between the swivel placket 16 and the steering arm 36.
(See Figure 4). Various suitable air handles,
Although stages can be employed, the pneumatic means 154 in this embodiment is substantially identical to the pneumatic means 42. Although the pneumatic means 154 may be coupled to any suitable pressure source, for ease of illustration the means 154 may be connected to the fourth
It is shown connected to an accumulator 86 in the figure.

As shown in FIG. 4, the pneumatic means 154 includes a piston 156 fixedly mounted to the swivel bracket, a cylinder 158 connected to the steering arm 36, and a pulp housing 160 fixedly mounted to the cylinder 158. , a pulp member 162 movable with respect to a pulp housing 160. Pulp member 1 in one direction
Movement of 62 causes movement of the steering arm 36 in that direction, and movement of the pulp member 162 in the other direction causes movement of the steering arm 36 in the other direction.

Pneumatic means 154 further includes: for selectively moving valve section side 162 relative to pulp housing 160;
and means actuated by the operator. Although various means may be employed, in the illustrated configuration the means for movement is provided by a remotely located steering mechanism 164 connected to the pulp member 162 by a push-pull cable 166.
including.

[Brief explanation of the drawing]

FIG. 1 is a side view of an outboard motor embodying various features of the invention; FIG. 2 is an enlarged, partially sectional, partially schematic view of the outboard motor power shift system; The figures shown, FIG. 3 is an enlarged, partially sectional, partially schematic illustration of an outboard motor power throttle system; FIG. 4 is an enlarged, partially schematic illustration of an outboard motor power steering system; 10... Ship propulsion device 20... Propulsion unit 24
... Propeller 26 ... Engine 28 ... Transmission 30 ... Throttle 32 ... Crankcase 34 ... Combustion chamber 42 ... Pneumatic means
44...Cylinder 46...Piston 53...
Pulp assembly 54...Pulp housing 56...
... Pulp member 78 ... Check valve 86 ... Accumulator 90 ... Check valve 102 ... Pneumatic means
104...Cylinder 106...Piston 103
...Pa/L/7" 7 assembly 114...Pulp housing 116...Pulp member 125...Check valve 146...Check valve 148...Accumulator 154...Pneumatic means 156.・Piston 15
8...Cylinder 160...Pulp housing 162
...Pulp parts (4 other people)

Claims (25)

[Claims] (1) A propulsion unit comprising a rotatably mounted propeller and an engine connected to and driven by the propeller; a member movable with respect to the propulsion unit; the propulsion unit and the member a pneumatic means actuated by an operator for selectively producing relative motion between the marine vessel propulsion system. (2) The pneumatic means operates in relation to a reference pressure, and the marine propulsion device further comprises a source of pressure different from the reference pressure, the pressure source being coupled to the pneumatic means. A marine vessel propulsion device according to claim 1. (3) the pressure source supplies a pressure greater than the reference pressure, and the marine propulsion device further includes an accumulator coupled to the pneumatic means and allows gas to flow from the pressure source to the accumulator; 3. The marine vessel propulsion device according to claim 2, further comprising a check valve that prevents the flow of gas from the accumulator to the pressure supply source. (4) the pressure source supplies a pressure lower than the reference pressure, and the marine vessel propulsion device further includes an accumulator coupled to the pneumatic means and allows gas to flow from the accumulator to the pressure source; The watercraft propulsion device according to claim 2, further comprising a check valve that prevents the flow of gas from the pressure supply source to the accumulator. (5) The watercraft propulsion system according to claim 2, wherein the engine further includes a crankcase, and the pressure supply source includes the crankcase. (6) The marine vessel propulsion system according to claim 2, wherein the engine further includes a combustion chamber, and the pressure supply source includes the combustion chamber. (7) The pneumatic means communicates with a cylinder, a piston slidably disposed within the cylinder and dividing the cylinder into opposing chambers, and communicating with the opposing chambers of the cylinder for supplying gas to the cylinder. 2. A watercraft propulsion system as claimed in claim 1, including a pulp assembly for controlling flow, one of said cylinder and piston being coupled to said member. (8) The other of the cylinder and the piston is fixed so as not to move in the axial direction of the cylinder, and the one of the cylinder and the piston is movable in the axial direction of the cylinder, and the pulp assembly includes a pulp housing communicating with an opposing chamber of the cylinder and a valve member movable relative to the pulp housing to control gas flow to the cylinder, the pulp housing and the valve member 8. The watercraft propulsion device according to claim 7, wherein one of the cylinder and the piston is connected to the one of the pistons so that they move together. (9) the pneumatic means is further actuated by an operator for selectively moving the other of the pulp housing and the valve member relative to the one of the pulp housing and the valve member; 9. A marine vessel propulsion system according to claim 8, comprising means for: (10) The marine vessel propulsion system according to claim 1, wherein the propulsion unit further includes a transmission coupling the engine to the propeller, and movement of the member relative to the propulsion unit controls the transmission. (11) The watercraft propulsion system according to claim 1, wherein the engine includes a throttle, and movement of the member relative to the propulsion unit controls the throttle. (12) The member is a mounting bracket configured to be fixed to the tail beam of the hull, and the propulsion unit is mounted to the mounting bracket, and the steering axis is substantially perpendicular to the bracket. 2. A marine vessel propulsion system as claimed in claim 1, wherein the pneumatic means causes a steering movement of the propulsion unit. (13) An apparatus comprising an engine provided with a combustion chamber, a movable member, and pneumatic means for moving the movable member, the pneumatic means communicating with the combustion chamber. (14) The device according to claim 13, wherein the engine includes a movable control mechanism, and the member is the control mechanism. (15) Claim 1, wherein the engine includes a throttle, and the movement of the member controls the throttle.
The device according to item 3. (16) the pneumatic means communicates with a cylinder, a piston slidably disposed within the cylinder and dividing the cylinder into opposing chambers, and the combustion chamber and the opposing chambers of the cylinder; 14. The apparatus of claim 13, further comprising a pulp assembly for controlling gas flow to the cylinder. (17) the pulp assembly includes a pulp housing that communicates with the combustion chamber and the opposing chamber of the cylinder and is movable relative to the pulp housing to control gas flow to the cylinder; 17. The device of claim 16, comprising a valve member comprising: (18) further comprising: an accumulator communicating with the pneumatic means; and a check valve allowing gas to flow from the combustion chamber to the accumulator and blocking gas from flowing from the accumulator to the combustion chamber; An apparatus according to claim 13. (19) An engine including a crankcase subjected to periodic conditions of relatively high pressure and low pressure, a movable member, and pneumatic means for moving the member, wherein the pneumatic means A device characterized in that it communicates with the crankcase. (20) The engine further includes a movable control mechanism,
Claim 19, wherein the member is the control mechanism.
Apparatus described in section. (21) Claim 1, wherein the engine includes a throttle, and the movement of the member controls the throttle.
The device according to item 9. (22) The pneumatic means includes a cylinder, a piston slidably disposed within the cylinder and dividing the cylinder into opposing chambers, and communicating with the crankcase and the opposing chambers of the cylinder, 20. The apparatus of claim 19, further comprising a pulp assembly for controlling the flow of gas to the pulp assembly. (23) the pulp assembly includes a pulp housing in communication with the crankcase and opposing chambers of the cylinder; and a valve movable with respect to the pulp housing to control the flow of gas to the cylinder. 23. The device of claim 22, comprising: a member. (24) further comprising: an accumulator communicating with the pneumatic means; and a check valve that allows gas to flow from the crankcase to the accumulator and blocks gas from flowing from the accumulator to the crankcase; An apparatus according to claim 19. (25) further comprising: an accumulator that communicates with the crankcase; and a check valve that allows gas to flow from the accumulator to the crankcase and blocks gas from flowing from the crankcase to the accumulator; An apparatus according to claim 19.