US2831474A - Overspeed shutdown controls for diesel engines - Google Patents

Description

April 22, 1958 D. 0. KING 'ET AL- OVERSPEED SHUTDOWN CONTROLS FOR DIESEL ENGINES Filed Sept. 1, 1954 wow INVENTORS DANIEL 0. KING BY FRED R. LOFTHOUSE AT ORNEYS Unit d S tes P td O OVERSPEED SHUTDOWN CONTROLS FOR DIESEL ENGINES Daniel 0. King, Marquette Heights, Pekin, and Fred R. Lofthouse, Manito, Ill., assignors to Caterpillar Tractor Co., Peoria, 111., a corporation of California Application September 1, 1954, Serial No. 453,652

2 Claims. .(Cl. 123-198) This invention relates to shutdown controls for diesel engines which operate automatically upon overspeeding of the engine and this application is a division of our application entitled, Emergency Shutdown Controls for Diesel Engines, filed May 11, 1953, Serial No. 354,372, now Patent No. 2,719,521.

In presently used overspeed governors or automatic overspeed shut-off mechanisms, there is usually a considerable time lag between initial overspeeding and shutting off of the engine so that some damage may be done to the engine before it stops.

It is an object of the present invention to provide an overspeed shutdown mechanism which is quick and positive in its action so that overspeeding is corrected instantly and without time for damage to the engine parts.

A further object of the invention is to provide an overspeed shutdown mechanism which is simple in construction and inexpensive to manufacture.

Further and more specific objects and advantages of the invention are made apparent in the following specification wherein a preferred form of the invention is described in detail by reference to the accompanying drawmg.

The drawing is a fragmentary view partially in section illustrating the general arrangement of an engine control mechanism of the kind in which a rack bar controlled by a governor is employed to rotate the plungers of a plurality of metering pumps which control delivery to the combustion chambers of the engine and also showing the relationship thereto of the overspeed shutdown control of the present invention.

In the drawing, the principle elements of a diesel engine fuel control mechanism are shown as including a control lever 10. A conventional governor spring 11 is connected with the lever and with a lever 11a fixed to a shaft 20 which also carries a two piece lever 12 of the kind disclosed in our assignees pending application, Serial No. 779,565, entitled Safety Control for Engine Governors, filed October 13, 1947.

A pair of fly weights 13 are carried and rotated by a shaft 131: driven by the engine through means not shown. The lever 12 is connected with a rack bar 14 which meshes with gears 14a on each of the plurality of fuel pumps, one of which is shown at 15. The foregoing structure is conventional and in this structure movement of the rack bar 14 toward the right increases engine speed while movement thereof to the left decreases engine speed and eventually results in shutdown of the engine.

A bell crank, a portion of which is shown at 16, contacts one end of the rack bar 14 preferably through an anti-friction roller as shown and movement of this bellcrank toward the left, as viewed in the drawing, in response to engine shutdown mechanism will move the rack bar to the left overcoming the tension of the spring 17 to cock the lever 12 and permit the engine to be shut down. The lever 12 with its spring 17 is herein illustrated as one means for permitting the rack bar 14 to move toward the left to accomplish shut down of the engine without overcoming the tendency of the main governor with its spring 11 to oppose such motion. There are various other devices for accomplishing this purpose any of which may be used in connection with the present invention.

The overspeed shutdown mechanism is shown in the drawing as supported by a bracket201, one end of which is connected to an enclosing housing by a pin 202 and the opposite end of which is secured to the same housing as by cap screws shown at 203. A pair of governor flyweights are carried on a shaft 91 journaled in this bracket and driven at a speed comparable to engine speed through a gear train, a part of which is illustrated at 92. As the flyweights 90 move outwardly about their pivots 93 in response to engine speed they engage and urge a sliding collar 94 toward the right. This collar engages a pin 96 slidably mounted in a part of the bracket 201 and this pin engages the lower end of a lever which is pivoted as at 97. The upper end of the lever 95 normally engages in a notch provided in a pawl 98 which is pivotally mounted as at 99. A latch member 100 formed on the top of the pawl 98 engages a shoulder 101 on a spring loaded piston 102.

With this construction, when the fiyweights 90 swing outwardly sufiiciently to overcome the preload on a spring 103 which opposes their outward movement, or in other words, when the engine operates at excess speed, the lever 95 is rotated in counter-clockwise direction about its pivot 97 and releases the plunger 102. The spring 105 of the plunger 102 forces the plunger toward the left as viewed in the drawing thus also swinging the lever 16 toward the left to move the rack bar 14 to its shutdown position without interfering with the setting of the governor spring 11.

In order to reset the overspeed control, the lever 46 is swung in a clockwise direction and since it is fixed to the shaft 45, it swings the bell crank 16- in a clockwise direction to permit the rack bar 14 to return to the operating position indicated by the tension on spring 11 and to urge plunger 102 toward the right. As plunger 102 moves to the right, a shoulder 107 thereon contacts an outwardly projecting tang of pawl 98 so that further movement of the plunger to the right will rock said pawl in a clockwise direction about pivot 99 permitting spring 106 to rock lever 95 in a clockwise direction about pivot 97 to position the pawl for locking the plunger 102 as shown in the drawing.

We claim:

1. In an emergency control for an engine having a longitudinally shiftable rod to control fuel supply, a lever pivotally mounted at one end and engaging at its opposite end an end of the shiftable rod, a manually actuated handle connected to said lever for manually overriding the normal engine control, a slidable plunger engaging said lever and having spring means associated therewith normally urging said plunger in a direction to shift said rod toward shutdown position, latch means normally holding said plunger in position, against the force of said spring, to permit normal operation of the shiftable rod, said latch means including a pawl engaging said plunger and a pivoted lever engaging said pawl to hold the same in latched position with respect to said plunger, and overspeed governor means actuated in response to overspeed of the engine to engage the opposite end of the last mentioned lever to release the pawl from said plunger and permit the latter to move the shiftable rod to shutdown position, said last'mentioned lever being normally spring biased into engaged position with said pawl whereby the first mentioned lever and its associated handle may be utilized to reset said plunger..

2. In an emergency control for an engine having a longitudinally shiftable rod to control fuel supply, a lever pivotally mounted at one end and engaging at its opposite 2,831,474 I j v I r 3 end an end of said shiftable rod, a manually actuated handle connected to "said lever for operating the same to manually override the normal engine control, a slidable plunger engaging said lever and having spring means associated therewith 'nor'mally urging said plunger in a 5 direction to shift said rod toward shutdown position, latch means normally holding said plunger in position, against the force of'said spring, to permit normal operation of the shiftable rod, said latch means including a pawl engaging said plunger and a pivoted lever engaging said pawl to hold the same in latched position with respect to the plunger, and overspeed governor means actuated in response to overspeed' of the engine and including a shiftahle collar, a pin element engageable by said shiftable collar and engaging the opposite end of '4' the last mentioned lever to release the pawl from the plunger and permit the latter to movethe shiftable rod to shutdown position, said last mentioned lever being normally spring biased into engaged position with said pawl whereby the first mentioned lever and its associated handle may be utilized to reset said plunger.

References Cited in the file of this patent UNITED STATES PATENTS 2,222,780 Miller Nov. 26, 1940 2,409,024 Dornbrook Oct. 8, 1946 2,555,818 Shirley June 5, 1951 FOREIGN PATENTS 179,774 Great Britain May 18, 1922 UNITED STATES PATENT OFFICE Certificate Patent No. 2,831,474 Patented April 22, 1958 Daniel 0. King and Fred R. Lofthouse Application having been made by Daniel C. King and Fred R. Lofthouse, the inventors named in the above identified patent, Caterpillar Tractor Company, a corporation of California, the assignee, and Dwight W. Parken, of lVashington, Illinois, for the issuance of a certificate under the provisions of Title 35, Section 256 of the United States Code, adding the name of Dwight W. Parken to the patent as a joint inventor, and a showing and proof of facts satisfying the requirements of the said section having been submitted, it is this 31st day of March, 1959, certified that the name of the said Dwight lV. Parken is hereby added to the said patent as a joint inventor with the said inventors named in the patent.

[SEAL] ARTHUR W. CROCKER, First Assistant Commissioner 0 7 Patents.

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