US 3044452 A
Description (OCR text may contain errors)
July 17, 1962 R. J. MCCRORY ETAL 3,044,452
STARTING DEVICE Original Filed May 16, 1958 2 Sheets-Sheet l INVENTORS ROLLIN J. McCRORY ROBERT W. KING United grates Patent 3,044,452 STARTING DEVICE Rollin J. McCrory, Worthington, and Robert W. King, Columbus, Ohio, assignors, by mesne assignments, to The Battelle Development Corporation, Columbus, Ohio, a corporation of Delaware Original application May 16, 1958, Ser. No. 735,795, new Patent No. 2,959,159, dated Nov. 8, 1960. Divided and this application Mar. 16, 1960, Ser. No. 15,464
2 Claims. (Cl. 1237) This invention relates to a starting device for internalcombustion engines of the free-piston type, and, particularly, to a starting device adaptable to free-piston engines having various constructions for meeting the requirements of different types of driven devices. This is a divisional application for our copending application entitled Free-Piston Internal-Combustion Apparatus, Serial No. 735,795, filed May 16, 1958, now Patent No. 2,959,159.
Free-piston engines are those in which the reciprocating motion of the piston, or pistons, is not mechanically restrained by the conventional connecting rod and crankshaft. Although most of the multipiston free-piston engines have mechanical connections between the pistons to maintain the proper phasing between the pistons, the end positions of the piston stroke are not established by the mechanical connections. The end positions of the piston stroke are established on each engine cycle by the energy released to'the work article or load that is being driven by the engine and the energies of the combustion process and the resilient rebound system.
Conventional starting mechanisms do not utilize the features of a pneumatically controlled free-piston engine. The starting mechanism herein described is especially adaptable to a free-piston engine having a pneumatic rebound system. It will be seen from the description to follow, that this invention may be utilized in a variety of constructions of free-piston engines and is adaptable, for
example, to engines for acivating compressors, tools, anvils, etc.
Briefly described, the starting mechanism comprises a support member fastened to the frame of an internalcombustion engine having a reciprocating free piston. A starting rod reciprocable in the frame is in communication with the piston and has a longitudinal slot in its side. A lever, pivotally supported on the support member has a handle at one end and a tip at the opposite end. When the lever is rotated the tip intersects the path of the slot in the reciprocating starting rod. Operating the handle rotates the tip engaged in the slot so as to reciprocate the piston and start the engine.
One feature of the present invention is a free-pistonengine starting mechanism by which a lever means is used to activate a free-piston engine having pneumatic rebound.
Another feature of the present invention is a starting device particularly suited for the reciprocating motion of a free-piston engine.
Other features and objects of the invention will be apparent from the attached drawings and the following description.
In the drawings:
FIG. 1 is an elevational, partly sectioned view of a free-piston engine having the starting mechanism of this invention;
FIG. 2 is a sectional, elevational view of a portion of a free-piston engine, showing a form of starting mechanism in connection therewith; and
FIG. 3 is a sectional, elevational view of another form of starting mechanism in accordance with this invention. 7
Referring to FIG. 1, the free-piston engine 50 com- 3,044,452 Patented July 17, 1962 IQC prises a block or frame 51 and a free piston 52 reciprocal therein. The frame 51 is provided with an internally bored combustion cylinder 53 and provided in communication therewith is a coaxial greater-diameter comcylinder 53 by means of the exhaust ports 57.
An annular intake manifold 63 is also provided in the frame 51 at a position further removed from the head end of the combustion cylinder. Communication is established between the combustion cylinder 53 and the intake manifold 63 by intake ports 58.
The head end 64 of the combustion cylinder 53 is provided with ignition means 65, such as a spark plug. Centrally positioned on the axis of the combustion cylinder 53, at the head end 64 is a fuel nozzle 66 of a fuel in jector, designated generally as 68.
The exhaust manifold 62 and the intake manifold 63 are provided with communication to the atmosphere by exhaust port 82 and air inlet 83.
As shown in FIG. 1, piston 52 is constructed with a minor-diameter portion 88 that is adapted to reciprocate in the combustion cylinder 53, being sealedwith the cylinder wall 61 by means of piston rings 89. At the opposite end, piston 52 is formed in a greater-diameter portion 90 which is adapted to reciprocate in a compression cylinder 54 and is sealed in connection therewith by means of the piston ring 91.
The free-piston engine 50 shown in FIG. 1 is provided with a piston rod 94 fastened to or formed integrally with the piston 52 and adapted to protrude through the base plate 55 and reciprocate therein through a bushing 95 with a seal 102. The piston rod 94, shown in FIG. 1, is constructed with a threaded end 96 to receive and hold a reciprocating tool.
Piston rod 94 is also provided with a starting slot 97 passing diametrically therethrough and having oppositely disposed perpendicular ends 98. A key bore 101 is provided through piston rod 94 at a position adjacent to and below the lower edge of slot 97 To cooperate with the starting slot 97, a starting lever 105 is provided. The lever 10 5 is formed with a lever tip 106 and a handle 107 and is supported on a pivot 108. Pivot 108 is located in the end of a starting lever trunnion 110.
Compression cylinder 54 is divided by the majordiameter portion or piston flange 90 into a bounce chamber 111 on the one side (lower side in FIG. 1) and a counterchamber 112 on the other side (upper side in FIG. 1) since, in FIG. 1, the piston 52 is shown at its upper most head end position, bounce chamber 111 is at its maximum volume, while counterchamber 112 is at minimum volume.
Near each end of the compression cylinder 54, pressurerelief valves 113 and 114 are provided in the frame 51. Relief valve 113 is in communication with counterchamber 112 by means of a conduit '115. Relief valve 114 is in communication with bounce chamber 111 by means of a conduit 116.
In order to start the engine 150, the tip 106 of lever 105 is inserted in slot 97. The handle 107 is then drawn upward which draws the piston down toward the mounting plate 55. This draw-down operation preparatory to starting is always necessary in a free-piston engine having pneumatic rebound, because the engine always stops with the piston at a position above bottom or lowest piston position. Having been at rest any length of time, combustion conditions in the combustion cylinder 53 Will, no longer be suitable for ignition, and the engine cannot be started until the piston 52 is brought to near the lowest position.
Once the piston has been drawn to the lower position,
the handle 107 is pushed brislcly downward, impelling the piston upward on the first compression stroke. Sufficient stroke is given the handle 107, when it is pushed downward, to carry the arc of tip 106 beyond the upper surface 98 of slot 97, and therefore free of piston rod 94, so that the first downward combustion stroke takes place "free of the starting mechanism.
The free-piston engine shown in FIG. 1 activates a reciprocating tool. In this instance the piston rod 94 protruding through the base plate 55 is also used as a starting rod for the starting mechanism. In instances where the free-piston engine is used to drive an impact tool, a pistonrod is unavailable as a starting rod. Such a device 'is 'shownin FIG. 2 Wherethe lower output end of a freepiston engine is integrally constructed with an impact tool.
' In this construction, engine frame '51 is fastened to a base plate which forms, in association with piston 90, the bounce chamber 111. Base 120 is constructed with a downwardly projecting cylindrical tool holder housing 121. A tool holder 122 and a retainer 123 support and retain a a tool 124 within the tool holder housing 121.
Tool 124 is provided with a flange 125 which controls reciprocation by means of its operation in a recess 126 of retainer 123. The tool 124 is positioned contiguous to and below an anvil 127 com-prising a striker portion 128, a flange portion 129 of larger diameter, and a hammer portion 130. Flange portion 129 is constructed to control the reciprocation of anvil 127 within the confines of an annular recess 131 which is formed in the base 120. Suitable sealing means 132 is provided between the anvil 127 and base 120 to seal chamber 111 from the atmosphere.
The piston 90 is provided with a bore having an annular recess 141. A starting rod 142 is positioned for reciprocation in base plate 120. Base plate 120 is counterbored to provide an annular recess 143 which receives a lug 144 that radially projects from the side of the starting rod 142 at its upper end. A longitudinal groove 145 connectsthe bottom surface of the piston 90 with recess 141 and is. of a width and depth necessary to conveniently pass lug 144. The remainder of the starting mechanism, which is in many respects the same as that for the reciprocating tool shown in FIG. 1, is supported from the base plate 120.
Rod 142 is provided with a starting slot passing diametrically therethrough and having oppositely disposed perpendicular ends 151. In addition to slot 150, a second slot 152 is provided in starting rod 142 disposed perpendicular to the first slot 150 and also having oppositely disposed perpendicular ends 153.
To cooperate with the starting slots 150 and 152 a starting lever 154 is formed with a lever tip 155 and a handle 156 and'is supported on a pivot 157. Pivot 157 is located in the end of a starting lever trunnion 158. The trunnion 158 is constnuoted with a slot 159 for longitudinal movement of pivot 157.
Key bore 160 is provided on the starting rod 142 below the slots 150 and 152. 7
Referring to FIG. 3, when free-piston engine 50 is constructed as an air compressor, the center position of the'piston 90 maybe constructed to receive a starting rod 14241. The construction is very similar to that of FIG. 2 except for location of some of the parts.
The piston 90 is provided with a bore 140a having an annular recess 141a. An axially disposed starting rod 142:: is positioned for reciprocation in the base 55a. Base plate 55a is counterbored on its longitudinal axis to'provide an annular recess 143a which receives a lug 144a that radially projects from the side of starting rod 142a at the upper end. A longitudinal groove 145a connects the bottom surfaceof piston 9i] with recess 141a. Groove 145a is of a width and depth necessary to conveniently pass lug 144a.
The starting mechanism of FIG. 3 is very similar to that of FIG. 2. The trunnion 158a is supported from the base plate 55d and has a slot 159a for longitudinal movement of pivot 157a. ,Two slots 150a and 152a are provided in starting rod 142a and are perpendicular to each other. Below the slots 150a and 152a, a key bore 160a is provided. A lever 154a, having a handle 156a at one end and a tip 155a at the opposite end, is supported on pivot 157a. I
As previously described for the operation of freepiston engine '50 as a reciprocating tool, it is necessary for piston 90 to be drawn to its lower'position, shown in FIGS. 2 and 3, preparatory to engine starting. To accomplish this, the starting rod 142 is raised into bore 141? by manipulation of handle 156. In order to align the lug 144 for passage through slot 145, starting rod 142 is rotated by means of key bore 160 ninety degrees. This aligns extractor slot 152 with lever 154 and permits the entrance of tip 155 therein. With pivot 157 at the lower position in slot 159, starting rod 142 may be controlled and inserted in bore 140. With starting rod 142 positioned within bore 140, tip 155 is removed from slot 152, permitting rotation of starting lever 142 ninety degrees. This operation of rotation moves lug 144 circumferentially in recess 141, securing the starting rod 142. With tip 155 engaged in slot 150, handle 156 may be manipulated to draw the piston down to position ready for the first upward compression stroke. With piston 90 at its lower position, starting rod 142 is rotated until lug 144 aligns with slot 145 and tip 155 of lever 154 is positioned in groove 152.
To start the engine, handle 156 is pushed briskly downward, forcing piston 90 upward on the first compression stroke. Handle 156 is pushed downward in rotation about pivot 157 through an angle great enough for tip 155 to pass out of groove 152, so that lever 154 is free of starting rod 142 on the first power stroke. On the immediately followingfirst power stroke, the upper end of starting rod 142 is thrown into counterbore 143 and is restrained from further downward movement by lug 144.
It will be understood, of course, that, while the forms of the invention herein shown and described, constitute preferred embodiments of the invent-ion, it is not intended to illustrate all possible forms of the invention. It will also be under-stood that the words used are words of description rather than words of limitation and that various changes, such as changes in shape, size, and arrangement of parts may be made Without departing from the spirit and scope of the invent-ion herein disclosed.
What is claimed is:
1. In a free-piston engine having a free piston reciprocable in a frame, a starting mechanism comprising: a support member fastened to said frame; a starting rod having two longitudinal slots in the side thereof, reciprocably and rotatably mounted 'in said frame, said rod connecting with said piston on rotation to a first position and disconnecting from said piston on rotation to a second position; a lever member pivotally supported in said support member and having a handle at one end and a tip at the opposite end, the movement of said tip in rotation said tip operable by said handle in rotation engaging said other slot and moving said piston in one direction.
2. In a free-piston engine having a free piston reciprocable in a frame, a starting mechanism comprising: a support member fastened to said frame; a starting rod, reciprocably and rotatably mounted in said frame having two longitudinal slots in the side thereof and a lug on the end thereof for engaging a receptacle on said piston and connecting with said piston on rotation to a first position and disconnecting from said piston on rotation to a second position; a key bore through said starting rod for rotating said starting rod about its longitudinal axis; a lever member pivotally supported in said support member and having a handle at one end and a tip at the opposite end, the
movement of said tip in rotation about said pivot intersecting the path of reciprocation of one of said slots at said first position, said tip operable by said handle in rotation engaging said one slot and reciprocating said piston, the movement of said tip in rotation about said pivot intersecting the path of reciprocation of the other of said slots at said second position, said tip operable by said handle in rotation engaging said other slot and moving said piston in one direction.
References Cited in the file of this patent FOREIGN PATENTS 330,574 Great Britain June 13, 1930