US2957351A - Centrifugal governor - Google Patents

Description

F. HEINZMANN CENTRIFUGAL GOVERNOR Oct. 25, 1960 Filed April 6, 1956 2 Sheets-Shout 1 INVENTOR. FRITZ HE/NZMANN ATTORNEYS Oct. 25, 1960 F. HEINZMANN CENTRIFUGAL GOVERNOR 2 Sheets-Sheet 2 Filed April 6, 1956 0 BM 2 915551555 I INVENTOR. FRITZ HE/NZMANN 75. .0. bwffla mi g ATTORNEYS United States Patent CENTRIFUGAL GOVERNOR Fritz Heinzmann, Albershausen, Kreis Goppingen,

iWurttemberg, Germany Filed Apr. 6, 1956, Ser. No. 576,732

Claims priority, application Germany Apr. 9, 1955 4 Claims. (Cl. 73-537) This invention relates to new and useful improvements in centrifugal governors. The invention more particularly relates to a centrifugal governor, which allows governing over a broad range of speeds, i.e., to an all-speed governor.

Centrifugal governors having springs, which directly oppose the centrifugal load, are known. Such governors, for example, have a rotatable governor body with a pair of opposed fly weights, pivotally connected thereto. The governor springs, which resiliently urge the fly weights together and toward the governor body, and thus act against the centrifugal load, are positioned about posts or spindles which extend radially from the governor body through the fly weights. The springs press on one end against the nuts or other holding members secured to the end of the spindle, and at the other end against the fly weight, as, for example, through a pivotal knifeedge bushing.

Governors of the above construction, as contrasted with conventional governors having axially arranged springs, have extremely low internal friction, are highly sensitive and efficient, and have a long life, due to the fact that there is no external load pressing upon the governor pivots. The centrifugal force of the fly weights is taken up directly by the springs, so that under all operating conditions the force required for control actuation by the governor, as, for example, through a control member, moved by the pivoting of the fly weights, is very small, as it is not necessary to counteract any spring force.

One object of this invention is a centrifugal governor of the above-mentioned constructional type having the advantages connected therewith, which allows speed governing over a broad range of speed with varying control characteristics in the different speed ranges. This and still further objects will become apparent from the following description, read in conjunction with the drawings, in which:

Fig. l is a side elevation partially in section of an embodiment of a centrifugal governor in accordance with the invention;

Fig. 2 shows the centrifugal force diagram of the governor of Fig. 1;

Figs. 3 and 4 are side elevations partially in section, showing still further embodiments of centrifugal governors in accordance with the invention;

Figs. 5 and 6 are centrifugal force diagrams of the governors of Figs. 3 and 4;

Fig. 7 is a side elevation partially in section, showing still another embodiment of a centrifugal governor in accordance with the invention; and

Fig. 8 shows the centrifugal force diagram of the governor of Fig. 7;

Fig. 9 shows the pivotal connection between the fly weight arms 1a and 1b and the control rod 14; and

Fig. shows the contact of the spring support bushing 3 with the fly weight 1.

The centrifugal governor in accordance with the invention has a rotatable governor body with a pair of opposed fly weights pivotally connected thereto. These fly weights will pivot outwardly, due to centrifugal force upon rotation of the governor body. Each of the fly weights has an opening defined therethrough extending in a direction substantially normal to the axis of rotation of the governor body. A pair of opposed spindles are radially connected to the governor body, extending through the openings in the fly weights substantially normal to the axis of rotation to the governor body. At least three separate springs are positioned around each spindle for resiliently opposing outward pivoting of the fly weights with at least three different compressive forces along the path of outward pivot thereof. The invention will be described in further detail with reference to the embodiments shown in the drawing.

In the embodiment as shown in Fig. 1, the governor has the fly Weights 1, which are pivotally connected to the governor body 2 by means of the pivots 15. The gov: ernor body has the central portion 2a, which maybe connected for rotation with a drive shaft. Upon such rotation the fly weights 1 will tend to pivot outwardly around the pivots 15, due to the centrifugal force. The fly weights 1 have openings defined therethrough extending in a direction substantially normal to the axis of rotation of the governor body. The spindles 6 are rigidly connected to the governor body and extend radial: ly there from through the openings in the fly weights; The axis of the spindles 6 is substantially normal to the axis of rotation of the governor body. The outward portion of the spindle is threaded and the 'spring-retain ing nuts 12 are screwed thereon. Connected to the fly weights 1 on the other side of the pivot 15 are the arms 1a and 1b, which form an integral part of the fly weights.

The arms 1a and the control rod 14 have a slotted hole. The arms 1b have a circular hole (see Fig. 9'). These arms are pivotally connected at the pivot joint 13 to'the control rod 14 of the governor. The control rod 14 is axially movable with respect to the governor body 2 and slides within the portion 2a of the governor body, which is rigidly screwed to the main portion 2 of the body. Upon pivoting of the fly weights outwardly, due to centrifugal force, around the pivot 15, the control rod 14 will be axially moved, due to the connection 13 with the arms 1a. The control rod 14 is connectedt'or control actuation in the conventional manner as, for example, to the distributor of an internal combustion engine;

The spindles 6 decrease in diameter toward their outer ends in two steps, forming the shoulders 5 and 10. Concentrically positioned around each spindle 6 is a spring support bushing 3 which has a large enough central bore to fit around the shoulders 5 and 10 and which rnovably presses against the fly weight 1. The spring support bushing 3 may have radially extensions on each side in the form of V-shaped knife edges to fit into corresponding V-shaped grooves in the fly weights, thus forming the contact between the fly weights and the bushings (see Fig. 10).

Additionally concentrically positioned around each spindle 6 is a bushing 7 and a bushing 9. The bushing 7 has a central bore large enough to fit around the shoulder 10 but small enough to contact the shoulder 5. The bushing 9 has a central bore small enough so that the same will contact and rest against the shoulder 10.

A first coil spring 4 is positioned between the spring support bushing 3 and the bushing 9, tending to push these bushings apart. A second spring 8 is positioned between the bushing 9 and the bushing 7, and a third spring 11 is positioned between the nut 12 and the outer side of the bushing 9.

With the governor in its rest position, the spring 11 is sufliciently tensioned, so that the bushing 9 is maintained firmly in contact with the shoulder 10. The spring 8 maintains the bushing 7 against the shoulder 5 and the spring 4, pressing against the bushing 9, presses the spring support bushing 3 against the fly weights, maintaining the same in the pivoted position against the governor body.

As the governor starts to rotate in its low speed or first speed stage, the spring 4 is slightly pressed as the fly weights move slightly outwardly, moving the bushing 3 toward the bushing 9. This stage of operation corresponds to the portion a--b of the force diagram shown in Fig. 2. Thus, at this first operating stage, the fly weights operate only against the force of the spring 4.

After the fly weights pivot out a little further at higher speed, the spring support bushing 3 contacts the bushing 7, moving the same with it and additionally compressing the spring 8. In this connection the springs 11 are precompressed and have sufficient tension so that the springs 4 and 8 may be compressed there against without causing movement or compression of the spring 11. In the second stage of operation, the fly weights move against the force of the springs 4 and 8, corresponding to the portion bc shown on the force diagram of Fig. 2. The spring 11 may be precompressed, so that its force just equals the combined force of the springs 4 and 8, when the fly weights move out to suflicient point so that the bushing 7 contacts the bottom of the bushing 9. Upon further rotational speed of the governor, the fly weights will move out further with the force of the springs 4 and 8 remaining constant and with the fly weights only operating against the force of the pre-loaded springs 11. This third stage is indicated by the portion c-d in the force diagram of Fig. 2. In the third operating stage the governor is therefore nearly astatic, the springs 11 being in a high degree precompressed, though during the first and second operating stages the governor is to a high degree static, the springs 4 and 8 being in a slight degree precompressed (see Fig. 2). This characteristic may be used for control whenever it is important to keep the regulation or speed drop in the upper part of the speed range small, while maintaining the regulation in the lower part of the speed range large.

The embodiment as shown in Fig. 3 is identical with that shown in Fig. 1, except that the stops in the form of the annular shoulders 5 and are eliminated, and in place of the spring support bushings 9 and 7, a single double-sided spring support in the form of the bushing 17 is provided. This spring support surrounds the spindle 6, and since no stops are provided, the same may move axially along the length of the spindle to the spring holding means in the form of the nut 12. The spring support in the form of the bushing 3 is identical with that shown in Fig. 1, except that the same is so dimensioned and constructed that it will come into supporting contact and carry the double-sided support 17 therewith, as the same is moved along the spindle toward the free end thereof.

A spring 16 is maintained compressed between the inner side of the double-sided spring support 17 and the governor body extending through the opening in the fly weight through which the spindle 6 extends. Another spring 4 surrounding the spindle 6 is maintained between spring support bushing 3 and the nut 12, and a third spring 8 is co-axially positioned within the spring 4 surrounding the spindle 6, and maintained between the nut 12 and the outer side of the double-sided spring support bushing 17. The spring 16, which is compressed in the normal position of the governor with the fly weight adjacent the governor body, opposes the force of the spring 8, and is so dimensioned and constructed that as the double-sided spring support 17 is moved toward the free end of the spindle 6, the same is relaxed.

In operation, as the governor body 14 is rotated in the conventional manner, the fly Weights pivot outwardly, due to the centrifugal force, moving the spring support bushing 3 outwardly along the spindle 6, compressing the spring 4, so that the fly Weights initially move solely against the force of this spring.

When the springs support 3 contacts the double-sided spring support 17 further outward movement of the fly weights I tend to compress both the spring 4 and the spring 8. The force of the spring 8, however, is initially opposed by the force of the spring 16, pressing in the opposite direction, so that the actual force which the outwardly moving fly weights must oppose, is the force of the spring 4 and the spring 8 minus the force of the spring 16. As the fly weights move further out, the spring 16 becomes relaxed, so that the fly weights must overcome increasing force, i.e., that the springs 4 and 8 without the aid of the spring 16. A centrifugal force diagram applicable to the governor of Fig. 3 is shown in Fig. 5. The portion cde represents the force of the spring 16, which is initially subtracted from the sum of forces of the springs 8 and 4, represented by g-k-d-f. If the springs 16 exert a smaller force, the force diagram of the governor will correspond to that shown in Fig. 6. Speed control with such construction is not instantly varied over the whole range of speeds with a neutral speed range m-n being inserted, whereby the governor becomes less static within the second stage. It is also possible to choose a third of higher speed stage ef smaller or greater in accordance with the length of the springs 16.

The governor of Fig. 4 corresponds exactly to that of Fig. 3, except that a stop in the form of a annular shoulder 5 is provided for the double-sided spring support, which is designated 18 in this embodiment. During the lower speed range of operation, the double-sided spring support 18 is supported on the annular shoulder 5, so that the spring 16 does not have to be initially compressed and need not have suflicient strength for this function. In the construction, the beginning of the second or intermediate speed range is exactly fixed at the point where the spring support 3 lifts the support 18 from the annular shoulder 5. In all other respects the operation of the governor is identical to that shown in Fig. 3 with in the first or low speed stage the fly weights operating against the force of the spring 4 alone, in the intermediate speed or second stage the fly Weights acting against the force of the springs 4 and 8 minus the force of the spring 16, and in the third high speed range acting against the force of the springs 4 and 8 alone.

The embodiment shown in Fig. 7 corresponds to the previously described embodiments except that only a single spring support, i.e., the bushing 3, is provided and three springs are concentrically positioned, one within the other, around the spindle 6. The springs 19, 20, and 21 are secured at their upper end to the spring-holding screws 12 by means of pins. The inner end of the spring 19 is maintained in contact with the bushing 3 with the fly weights 1 at their normal rest position adjacent the governor body. The spring 20 is somewhat shorter than the spring 19 and at this position is spaced at some distance from the bushing 3. The spring 21 is somewhat shorter than both the springs 19 and 20 and spaced at a still further distance from the bushing 3.

As the governor body is rotated and the fly weights move centrifugally outwardly, first the spring 19 is compressed, so that the fly weights move solely against the force of this spring. After the fly weights move out a certain distance, the bushing 3 contacts the spring 20, so that the same begins to become compressed and the fly weights move against the combined force of the springs 19 and 20. When the fly weights move out still further, the bushing 3 contacts the spring 21, so that the fly weights will move against the combined forces of the springs 19, 20, and 21.

The force diagram 0pqr of the governor of Fig. 7 is shown in Fig. 8. As the elastic force curve of a cylindrical helical spring is a straight line and as the speed is a quadratic function of the elastic force and centrifugal force, the speed curve is parabolic. Within the lower portion of the speed range, the regulation is therefore considerably greater than within the upper part. In accordance with the embodiment of Fig. 7, the springs 19, 20, and 21 are made effective one after the other as the fly weight moves outwardly. This produces a polygonal elastic force diagram as is required in order to obtain a low degree of variability of regulation. The embodiment of Fig. 7 is particularly suitable for uses which require a low degree of variability of regulation over the whole speed range, while not requiring this regulation to be particularly small.

While the invention has been described in detail with reference to the specific embodiment shown, various changes and modifications will become apparent to the skilled artisan which fall within the spirit of the invention and the scope of the appended claims.

I claim:

1. In a centrifugal governor comprising a rotatable governor body, a pair of opposed fly weights pivotally connected to said governor body for pivoting outwardly due to centrifugal force upon rotation of said governor or body, an opening defined through each of said fly weights extending in a direction substantially normal to the axis of rotation of the governor body and a pair of opposed spindles connected to said governor body extending through said openings substantially normal to the axis of rotation of the governor body, the improvement which comprises for each spindle a first, a second, and a third spring support surrounding the spindle and axially movable there along, said first spring support being axially movable along substantially the entire length of the spindle and positioned in movable contact with the fly weight through which the spindle extends, said second spring support being axially movable between substantially the outer end portion of said spindle and a first stop positioned at the intermediate portion of said spindle, said third spring support being positioned between said first and second spring supports and axially movable along the spindle between substantially the outer end portion thereof and a second stop positioned between said first stop and the inner end of the spindle,

said first spring support being dimensioned to contact said third spring support and carry the same therewith upon axial movement along the spindle toward the free end thereof, at least one of said first and third spring supports being dimensioned to contact said second spring support and carry the same therewith upon axial movement along the spindle toward the free end thereof, and spring-holding means positioned at the free end portion of said spindle, a first spring mounted between said first and second spring support, a second spring mounted between said second and third spring supports, and a third spring mounted between said second spring support and said spring-holding means.

2. Centrifugal governor according to claim 1, in which said third spring has a compressive force in its normally extended position with the fly weights positioned adjacent the governor body at least substantially equal to the combined compressive forces of said first and second springs in their compressed position with said spring supports in contact with each other.

3. Centrifugal governor according to claim 2, in which said second spring is concentrically positioned within said first spring.

4. Centrifugal governor according to claim 3, in which said stops are defined by annular shoulders on said spindle, said second stop having a larger diameter than said first stop.

References Cited in the file of this patent UNITED STATES PATENTS 654,057 Sprado Apr. 5, 1910 2,096,203 Schnurle et al. Oct. 19, 1937 2,139,194 Lichtenstein Dec. 6, 1938 2,631,025 Bone Mar. 10, 1953 FOREIGN PATENTS 177,055 Austria Dec. 28, 1953 843,959 Germany July 14, 1952 384,976 Great Britain Jan. 12, 1933 691,011 Great Britain May 6, 1953 (SEAL) UNITED STATES PATENT OFFICE CERTIFICATION OF CORRECTION Patent No. 2 957 35l October 25 1960 Fritz Heinzmann It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

In the grant line 3 for Wurttemberg" read Wiirttemberg em inthe heading to the printed specification line 3 for Goppingen read G'cippingen -==3 line 4 for "Wurttemberg read Wurttemberg column 1 line 64 strike out "and"; column 2 line 53, for -"radially" read radial column 3 line 16 and 17 for "springs 4 and 8' read springs 4 line 72 for body 14" read w body 2 column 4 line 3 for "springs support read spring support line 13 for "that the read that of the line 35 for "the construction" read this construction column 6, line' 31 list of references cited under "UNITED STATES PATENTS for 654L,O5T" read 954 O5'Z e Signed and sealed this 18th day of April 1961e Attest: ERNEST w, SWIDER DAVID L D Attesting Officer Commissioner of Patents

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