US2423516A

US2423516A - Safety device for valve gear of expansible chamber motors

Info

Publication number: US2423516A
Application number: US622596A
Authority: US
Inventors: Naab Julius; Ostwald Richard
Original assignee: Ingersoll Rand Co
Current assignee: Ingersoll Rand Co
Priority date: 1945-10-16
Filing date: 1945-10-16
Publication date: 1947-07-08
Anticipated expiration: 1964-07-08

Description

July 8, 1947. J. NAAB ETAL SAFETY DEVICE FOR VALVE GEAR OF EXPANSIBLE CHAMBER MOTORS Filed Oct. 16, 1945 7 INVENTORS THE R ATTORN EY- Patented July 8, 1947 SAFETY DEVICE FOR VALVE GEAR OF EXPANSIBLE CHAll/IBER- MOTORS Julius Naab and Richard Ostwald, Easton, Pa., assignors to Ingersoll-Rand Company, New York, N. Y., a corporation of New Jersey Application October 16, 1945, Serial No. 622,596

3 Claims.

This invention relates to safety devices, and more particularly to a safety device for a pressure fluid actuated engine of the reciprocatory piston type.

One object of the invention is to prevent the operation of the engine at unsafe speeds.

A more specific object is to prevent the distribution of pressure fluid to the piston chamber whenever the speed of the engine exceeds a certain predetermined rate.

Other objects will be in part obvious and in part pointed out hereinafter.

In the drawings accompanying this specification and in which similar reference numerals refer to similar parts,

Figure l is a longitudinal side elevation of an engine equipped with a safety device constructed in accordance with the practice of the invention.

Figure 2 is an enlarged plan view, partly broken away, taken through Figure 1 on the line 2-2 looking in the direction indicated by the arrows, and

Figure 3 is a longitudinal view, partly in section, taken through Figure 2 on the line 3-3 looking in the direction indicated by the arrows.

Referring more particularly to the drawings, the invention isshown applied to a horizontal engine 20 having the usual bed plate 2| and a crank shaft 22 therein carrying a fly wheel 23. On one end of the bed plate is a distance piece 24 to support a cylinder 25 having a piston chamber 26 to accommodate a reciprocatory piston 21 the rod 28 of which may be operatively connected in any Well known manner, to the crank shaft 22.

At the side of the cylinder 25 is a steam chest 29 fcontaining a bushing 30 the interior of which constitutes a valve chamber 3| and communicates with the front and rear ends of the piston chamber 26 through

passages

32 and 33, respectively. The intermediate portion of the steam chest is recessed to provide a supply chamber 34 that communicates with the intermediate portion of the valve chamber 3| through ports 35 in the bushing 30, and the admission of steam into the chamber 34 is controlled by a hand-operated throttle valve 36 on top of the steam chest and communicating with the chamber 34 through a passage 31.

The steam chest is further recessed to provide

exhaust chambers

38 and 39 at the front and rear ends, respectively, of the valve chamber, and said exhaust chambers may be connected by a passage (not shown) having an exhaust outlet 40.

The ports 4| and 42 through which the

passages

32 and 33, respectively, communicate with the valve chamber 3| are located at suitably spaced distances from the ends of the valve chamber and are controlled by the heads 43 and 44 of a valve 45 reciprocable in the valve chamber. The heads 43 and 44 are connected by a stem 45 and are of the same diameter so that their opposed inner surfaces 41 will be of equal area and the steam acting constantly tl1ereagainst will be ineffective to shift the valve.

The linkage serving to impart reciprocatory motion to the valve 45 is connected to the crank shaft 22. It comprises a rod 48 that extends axially from the head 43 of the valve and slidably through a cover plate 49, at the adjacent end or the valve chest 29, and through an end of a bracket 53 spaced from and joined to the cover plate 49 by webs 51. The intermediate portion 52 of the rod 48 is threaded through an end of a yoke 53 which carries, near its opposite end, a guide bar 54 arranged in parallelism with the rod 48. One end of the bar 54 is slidable in a bore 55 in the bracket 55] and its opposite end 56 is slidable in a bushing 57 arranged within a cylindrical enlargement 58 at the edge of the plate 49. On the end of the yoke, adjacent the bar 54, is an axle 53 that extends transversely through an end of an arm '60, and a washer 6| overlying the end of the axle and secured thereto by a screw 62 retains the arm 69 on the axle.

The arm 50 has a free running fit on the axle 59. Its opposite end is hollow, having a bore 83 to receive an end of a rod 64 the opposite end of which is mounted, for pivotal movement, upon a pin 65 positioned eccentrically on the end of the crank shaft 22. The rod (54 has a slide fit in the bore 63 and is connected to the arm 69 by a pin 6% which extends through the rod 64 and through the opposed sides of the arm and is so proportioned, for strength, that it will safely withstand the strains to which it is subjected for normally driving the valve 45 but will break when subjected to abnormal strains.

The means provided for causing such breaking of the pin 36 is actuated by the linkage which drives the valve 45 and is preferably arranged, as shown, on the end 55 of the guide bar 54. It comprises a rod 67 that is threadedly connected to the end 56 of the bar .54, to extend axially thereof, and at an intermediate portion of the rod fil' is a cylindrical enlargement 58 to act as a stop member for a weight 69 encircling the rod 61 between the enlargement 68 and the bar 54.

The weight 69 has a sliding fit in the bushing 57 and on the rod 6! and is of less length than the distance between the enlargement 68 and the end of the bar 54 to permit of a limited degree of endwise movement on the rod 61. Near the inner end of the weight is an external annu lar groove to accommodate an expansion ring H which is normally retained entirely within the groove 10 by the bushing 51 but will expand to lie partly within the groove 10 and partly over the end surface of the bushing 51 when the weight occupies its outermost limiting position in abutment with the enlargement 58.

Normally, however, the weight 69' abuts the end 56 of the bar 54 and is held in this position by a spring 72 encircling the rod 6'! and seating against the outer end of the weight. The opposite end of the spring engages a spring seat 13 slidable upon the rod 61, and a nut 14 is threaded on the rod ill, against the seat 73, to Vary the force of the spring 12.

Preferably a cup-like casing '15 is disposed telescopically upon the end of the enlargement 58 to protect the rod 67 and the associated parts from exposure to dust and dirt.

During the operation 'of the engine at normal speed, and with the spring '12 correctly adjusted to hold the weight 69 against the bar 54, the weight will reciprocate with the valve 45, and its range of movement will be of only such extent that the expansion ring II will not pass beyond the end of the bushing 51 but will remain contracted within the groove 10.

In the event that the engine speed rises to an excessive rate, as when the governing apparatus serving to control the speed of the engine fails to function properly, the consequent accelerating speed will cause the weight 69 to be projected relatively to the bar 54 against the enlargement 68. This movement of the weight will cam the expansion ring H out of the bushing 51 and the ring will then expand and engage the end surface of the bushing 51, thereby forming an interlocking connection between the bar 54 and the casing of the engine. The following retractive stroke of the rod 64 will cause the pin 66 to be sheared off at the cooperating surfaces of the rod 64 and the arm 60. In this way the driving connection between the crank shaft 22' and the valve 45 will be broken.

The valve will then remain stationary in its rearmost limiting position to valve pressurefluid into the rearward end of the piston chamber 25 for holding the piston immovable.

We claim:

1. A safety device for a pressure fluid actuated engine, comp-rising a casing having a piston chamber and supply passages leading to the ends of the piston chamber, a reciprocatory valve to control the supply passages, a driver, linkage to transmit motion from the driver to the valve having in its organization a connector adapted to break when subjected to an abnormal strain for detaching the driver from the valve, and means reciprocable with the valve and acting responsively to a super-normal speed of the driver for interlockingly engaging the casing to cause the breaking of the connector. w W

2. A safety device for a pressure fluid actuated engine, comprising a casing having a piston chamber and supply passages leading to the ends of the piston chamber, a reciprocatory valve to control the supply pasasges, a driver, linkage to transmit motion from the driver to the valve having in its organization a pair of members and a connector therefor adapted to break when subjected to an abnormal strain for detaching the driver from the valve, a weight actuated by the linkage to normally reciprocate at the rate of speed of the valve and being projected beyond its normal range of movement at a super-normal speed of the driver, and means carried by the weight acting to hold one member stationary and thereby enable the other member to break the connector whenever the weight is projected beyond its normal range of movement.

3. A safety device for a pressure fluid actuated engine, comprising a casing having a piston chamber and supply passages leading to the ends of the piston chamber, a riciprocatory valve to control the supply pasages, a driver, linkage to transmit motion from the driver to the valve having in its organization a pair of members and a connector therefor adapted to break when subjected to an abnormal strain for detaching the driver from the valve, a spring-pressed weight actuated by the linkage to normally reciprocate at the rate of speed of the valve and being projected beyond its normal range of movement at a supernonnal speed or. the driver, a guide for the weight, and an expansion ring in the periphery of the weight to eiiect an interlocking connection between the weight and the guide upon projectile motion of the Weight for holding one member stationary and thereby enable the other member to break the connector.

JULIUS NAAB. RICHARD OSTWALD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 689,784 Bradbury et a1. Dec. 24, 1901 989,062 Sargent Apr. 11, 1911 1,363,067 TWa Dec. 21, 1920