US3552410A

US3552410A - Centrifugal governor having a spring-adjusting ring and valve-cleaning means

Info

Publication number: US3552410A
Authority: US
Inventors: Lester A Amtsberg
Original assignee: Chicago Pneumatic Tool Co LLC
Current assignee: Chicago Pneumatic Tool Co LLC
Priority date: 1968-12-13
Filing date: 1968-12-13
Publication date: 1971-01-05
Anticipated expiration: 1988-01-05
Also published as: GB1251119A

Abstract

A speed-responsive centrifugal governor is mounted upon the rotor portion of a pneumatic motor, the governor having a sleeve valve which is slidable relative to an inlet against the force of a compression spring by means of centrifugally actuable weights so as to regulate air flow to the motor accordingly as the load and speed of the motor varies. Tension of the spring can be selectively varied by means of an adjustable ring so as to prevent the speed of the motor from exceeding a predesigned maximum rate. The ring is retained upon the spring by means of pins fixed overhead in the body of the governor, each of which pins is releasably engaged by a selected one of a plurality of notches formed in the periphery of the ring. By angularly adjusting the ring to engage the pins with other notches at selectively higher or lower levels, the tension of the spring can be varied. A shaft clamping the governor to the motor has a helical surface groove which is adapted during sliding of the valve to allow inlet air to sweep the opposed sliding surfaces of the valve and shaft clean of dirt that might otherwise inhibit free valve movement.

Description

O United States Patent n 13,552,410

[72] Inventor Lester A. Amtsberg 2,485,514 10/1949 Sturvock 137/56 Utica, N.Y. 2,674,229 4/1954 Karlen 137/56X [21] Appl. No. 783,596 3,013,790 12/1961 Anderson 137/510X [221 Ned 1968 Primary Examiner--Clarence R. Gordon [45] Patented 1971 Attorney-Stephen] Rudy [73] Assignee Chicago Pneumatic Tool Company New York, N.Y. a corporation Jersey ABSTRACT: A speed-responsive centrifugal governor is mounted upon the rotor portion of a pneumatic motor, the [54] CENTRIFUGAL GOVERNOR HAVING A SPRING governor having a sleeve valve which is slidable relative to an ADJUSTING RING AND VALVBCLEANING inlet against the force of a compression spring by means of MEANS centnfugally actuable weights so as to regulate air flow to the 13 Chins 6 Drawing Figs motor accordingly as the load and speed of the motor varies. Tension of the spring can be selectively varied by means of an m 137/56; adjustable ring so as to prevent the speed of the motor from 73/544? 267/] exceeding a predesigned maximum rate. The ring is retained [51 Int. Cl. 605d 13/10 upon the Spring by means f pins fi d overhead in the body f [50] Field of Search 137/53, 54, the governor, each f which pins is releasahly engaged by a 56, 5-10; 73/544 535, 537, 538, 539, selected one of a plurality of notches formed in the periphery 550i 267/1 of the ring. By angularly adjusting the ring to engage the pins with other notches at selectively higher or lower levels, the [56] References Cited tension of the spring can be varied. A shaft clamping the UNITED STATES PATENTS governor to the motor has a helical surface groove which is 1,938,655 12/1933 Gibson 73/539X adapted during sliding of the valve to allow inlet air to sweep 2,149,645 3/1939 Sittert..... l37/56X the opposed sliding surfaces of the valve and shaft clean of dirt 2,402,972 7/1946 Mitchell 137/56 that might otherwise inhibit free valve movement.

justing notches;-

This invention 'relates" to speed-responsive centrifugal governors ofa type having a governor spring-biased air supply valve which is slidableby centrifugally actuable means from one condition to another against the bias of-the spring.

Governors of this general nature-are. known as having a governor spring adjusting screw ring which must be threaded selectively in one direction or another to vary the tension, of

the spring. Rings of this known nature tend to loosen under vibration from their adjusted condition so that some separate form of locking means is requiredto' secure the adjusted position of the ring. The'adjusting ring of the present invention is not threaded. It utilizes a series of selectable notches having different levels *in'conjunction with pin elements to obtain selective adjustment of the governor spring. The ring becomes I automatically locked in its adjusted position upon engagement of the pins with the selected notches.-

Another fault of such known governors is a tendency of'dirt to accumulate between the valve and its guide so as to inhibit free movement of the valve. In the governor of the present invention, a helical groove is provided around the peripheral surface of the valve guide which'permits inlet air to sweep over-the contacting surfaces of the valve andthe guide to clean away any dirt tending to accumulate thereon.

BRIEF DESCRIPTION OF DRAWING In the accompanying drawing l a FIG. Us a sectional view of a speed responsive centrifugal governor embodying the invention in whichthe governor valve is shown in its'norrhal fully open condition relative to itsv ea v 1 x FIG. 2 is a view similar tothat of FIG I but showing the valve to have beencentrifugally moved to a substantially closed condition relative to its seat; i

FIG. 3 is a detail of the'top end of the adjusting ring engaged by the latch pins;

FIG. 4 is a developed view of one of the segments of the ad FIG. 5 is a detailof the bottom of the governor bodyand its I retainer the retainerbeing broken away in part; and,

FIG. 6'isza section taken on line-6l-6 of FIG. -5 with a a.- tion shownin full. I

DETAILED DESCRIPTION or PREFERRED.

IHEMBODIMENT In the accompanying drawing is disclosed a general housing to, in alower portion'of which is housed a conventional airdriven motor 11 of the slidable vane type. The rotor 12 of the motor has an axially projecting shaft end l3v supported in a bearing member 140i a'bearing block 15. The latter is rigid with the housing. A speed-responsive centrifugalgovernor assembly 16 atranged within the, housing is mounted to the rotor shaft so as to rotate as a unit with the rotor. It functions to regulateflow of operating air to the motor, accordingly, as the load and speed of the motor varies and, in doing so, serves to control the operating speed of the motor so that it will not exceed a predetermined maximum;

The governor assembly includes a supporting cage or body I7(FIGS. 1, 2, 5,6) having a cylindrical upper'portion 18' and a lower depending rectangular portionl 9. The latter portion is seated betweenthe sidewalls 21 of a retainer 22 having a U- form in cros section. An end ofthe rotor shaft projecting beyond the bearingfl4 hasa' splineddriving connection 23 with the retainer; and'the retainer, together with the governor body 17, are rigidly clamped to therotor shaft by means of a governor shaft 24. The latter has a screw portion 25 of reduced diameter which passes through the bottom-wall26 of ring showingthe staircase arrangement of a group of the governor body. It is threaded tightly into an axial bore of the rotor shaft so as to draw an upper larger diameter shaft portion 28 into abutment with the bottom wall 26. Shaft portion 28 extends axially of a recess 40 of the governor body. A

clearance 30 to and from closedcondition relative to a valve seat 32. The clearance 30 communicates an air supply connected inlet passage 31 in the valve seat with the interior chamber 33 of the housing, which chamber in turn leads through passage means 34 to themotor.

The valve is slidable by means of a pair of centrifugally actuable flyweights 35 across the clearance 31 to closed condition so as to block air flow to the motor. E'ach'weight is pivoted in a separate bifurcation 36 in the lower portion of the governor body upon a pin 37 fixed in the opposed walls of the bifurcation. Each weight has an extended foot 38 underlying an annular terminal flange 39 of the valve. As the bodies of the weights are caused to swing outwardly, the foot portions force the valve along the shaft across the clearance 30.

The weights have a normal condition, as in FIG. I, under thebias of a return spring 41, in which'condition the valve is fully open. In the normal position of the weights, the foot portions 38 test under the load of the spring upon the underlying surface of the retainer 22. The spring is disposed between the valves flange 39 and an annular recessed shoulder of an overhead ring 42. The ring is arranged for making adjustments in the tension of the spring. The ring is releasably held seated upon the spring against endwiseescape and is releasably restrained against relative angular movement by means of a group of latch. pins 43 (FIGS. 2, 3). The pins, which here are three in number, are fixed in the sidewall of the cylindrical portion 17 of the governor body and are spaced angularly ecjually apart. Each pin projects radially and at the same level as the other pins into a separate separate of a separate group of notches formed in the upper peripheral edge of the ring.

{The ring (FIGS. 14) in conjunction with the pins represents an important feature of this invention; and is considered to be a desired technical advance in means for making selective adjustments in the tension of the governor spring of a speed responsive centrifugal governor. Adjustments made in the tension of the spring result in corresponding variations in the rated control speed of the driving motor 11.

The ring is formed with three identical groups of notches -44, each group occupying an equal segmental portion of the periphery of the ring. The notches are arranged in stepwise orstaircase order in each group in such manner that each succeeding notch in a group is at a higher level than the preceding one. The lowest level is occupied by the first notch 45 of the group. Eachgroup is spacedfrom the next by a slot 46 which extends axially from the top to the bottom of the periphery of the ring. Each slot 46 is defined by a wall 47 (FIG. 4) provided at'the end of one group, and by a relatively shorter wall 48 provided at the start of the next succeeding group. Wall 48 terminates short of the upper peripheral edge of the ring so as to facilitate assembly of the ring to the governor in a manner as will now be described.

In the assembly process, the ring is first manually centered atop the valve spring 41 with each of its slots 46 registered with a separate one of the pins 43. The ring is then depressed axially against the spring over the pins until the top 49 of the short wall 48 of each slot is at a level below that of the pin. The

ring is then rotated angularly to bring the first notch 45 in each depressed and indexed angularly as needed to register and engage the pins in selected notches of a higher level. Obviously,

indexing the ring from a higher level of notch engagement to a lower level will affect a corresponding decrease in the spring tension. The notches are of generous depth so that the ring will be securely locked by the pins in any indexed position and will not be caused to ride from one notch level to the next as a consequence of shock or vibration occurring during operation of the motor.

To facilitate assembly and indexing of the ring relative to the pins, the ring is provided in its top surface with a pair of opposed recesses or wells 51 (FIG. 3). These are subject to being engaged by means of a suitable pronged tool or spanner which can be manipulated to first depress the ring as needed against the resistance of the spring and to then index the ring angularly to register selected notches of thering with the pins.

To avoid the possibility of dirt accumulations between the valve 29 and the governor shaft 24 that might inhibit sliding movement of the valve, the governor shaft is designed to permit inlet air to sweep over the inner surface of the valve during operation of the governor. To this end, the peripheral surface of the upper portion 28 of the governor shaft is provided with a helical groove 52. The groove begins at the upper top edge of the shaft and terminates at its bottom end above the bottom wall 26 of the lower portion of the governor body. In the normal fully open condition of the valve, as in FIG. 1, the valve covers over the helical groove with the exception of the upper terminal or starting end 53 (FIG. 2) of the groove, which end is directly opposite the inlet 31. Accordingly, while the valve has this normal condition, the full volume of air from the inlet passage flows around the governor through

passages

33 and 34 to the motor. In its normal condition, the valve blocks inlet air entering the helical groove from flowing through the bottom end of the groove. Upon the speed of the motor exceeding a predetermined limit, as determined by the tension of the governor spring, the flyweights 35 are centrifugally actuated to slide the valve toward its seat to progressively block the volume of air flow through the clearance 31 to the motor. The speed of the motor is accordingly retarded. In the sliding movement of the valve toward its seat, it uncovers the lower terminal end 54 of the helical groove sufficiently. to allow inlet air to flow in restricted volume through the helical groove. The inlet air sweeps forcefully through the helical groove and over the inner surface of the valve to free the opposed surfaces of the valve and shaft of any dirt tending to accumulate therein. The air stream exiting from the bottom end 54 of the groove passes around the weights 35 and through the bifurcated openings 36 in the wall of the governor body to be finally exhausted through the motor. At about the time that the valve reaches its seat, the air stream passing through the helical groove 52 is substantially at its full force. The entire governor assembly as described above rotates as a unit with the rotor shaft. As it rotates, an annular protuberance 55 centrally of the underside of the retainer 22 bears upon the inner race of the bearing 14.

Obviously, as the speed of the motor is retarded, the governor spring 41 progressively expands to restore the valve and weights to original condition and thus the speed of the governor is held to a predesigned maximum. This maximum, as earlier explained, may be varied by making selective adjustments in the tension ofthe spring 4].

We claim:

1. In a speed-responsive centrifugal governor including a ,body having an axially extending recess in its top end, a cylindrical guide shaft rigid with the body extending axially of the recess, a cylindrical control sleeve about the guide shaft having relative axial movement, a compression spring biasing the sleeve axially upon the guide shaft inwardly of the recess, centrifugfly actuabie means responsive to a predetermined rotating speed of the body to slide the sleeve along the shaft outwardly of the recess against the bias of the spring, and means disposed within the recess selectively operable for adjusting the tension of the spring; groove means extending about the surface of the guide shaft for substantially the length of the latter for conducting a stream of live air over the interior surface of the sleeve surrounding the guide shaft.

2. In a speed-responsive centrifugal governor as in claim 1, wherein a retainer bracket engaging the body has an axial bore adapted for splined engagement with a rotor shaft.

3. In a speed-responsive centrifugal governor as in claim 2, wherein the guide shaft has an annular shoulder overlying a bottom wall of the body and has'a screw'por'tion of reduced diameter depending through the said bo t'tom'wall adapted for internal threaded engagement'with a rotor shaft. I

4. ln a speed-responsive centrifugal governor as 'in'claim 1, wherein the sleeve has a normalcondi'tion under the 'bias of the spring in which an exit end of the groove means is blocked from communicating with the recess. 5

5-. In a speed-responsive centrifugal governor as in claim 4, wherein bifurcations are provided in the body, and the exit end of the groove means has communication through the recess with the bifurcations following a predetermined degree of axial movement of the sleeve against the bias of the spring.

6. In a speed-responsive centrifugal governor as in claim 2, including a housing providing a chamber in which the body of the governor is disposed, the housing having a valve seat in spaced axial relation to the guide shaft and to the sleeve defining a live air inlet passage communicating with the chamber, the chamber being adapted for connection with a rotor chamber, and the sleeve being a valve having an end adapted to close upon the seat so as to block the inlet passage from the chamber as a consequence of a predetermined degree of outward movement of the sleeve. i g i 7. In a speed-responsive centrifugal governor as in claim 1, wherein the means for adjusting'the tension of the spring comprises a ring separate from the body and seated atop the spring, the ring having a plurality of notches arranged angularly about its periphery, a plurality 'ofpins numbering less than the number of notches projecting-radially from the body in overlying relation to the ring, each pin being at the same level as the others, each pin being releasably engaged by a separate notch, each notch engaged'by a pin being at the same level as the other engaged notches, the ring being tensioned by the spring in such engaged relation and being selectively subject to axial disengagement from said pins and selective angular adjustment so as to engage notches at other levels withthe pms.

8. In a speed-responsive centrifugal governor as in claim 7, wherein the notches are arranged in identical groups, each group being separated one from the other by a space and each group occupying a separate segment of the ring, the notches in each group succeeding one another, each notch in the order of succession being at a level higher than that of the preceding notch, and the pins being spaced angularly equally apart so that each pin is subject to engagement with the notches of one of the groups.

9. In a speed-responsive centrifugal governor as in claim 8, wherein each slot is registrable with and adapted to be passed over a separate one of the pins accordingly as the ring is selectively moved axially in one direction or the other.

10. In a speed-responsive centrifugal governor including a governor body adapted at its bottom and for attachment tda rotary drive shaft and having an annular recess opening through its top end, a cylindrical slidable control memberIa yieldable compression spring having one end abutting the control member and biasing it axially toward the bottom of the recess, and means responsive to centrifugal force developing during rotation of the governor body tending to move the control member axially against the bias of the spring; the improvement comprising means for selectively adjusting the degree of bias of the spring upon the control member, the adjusting means comprising a ring separate from the governor body having a central area abutting the top end of the spring,.a plurality of notches having various levels formed about the periphery of the ring, a plurality of pins extending radially from the governor body at identical fixed levels in overlying relation to the ring, a separate one of the notches being in releasable pressed engagement under the force of the spring with a separate one of the pins, each notch engaged by a pin being at the same i to the groups and arespaced angularly equally apart, and the notches in each group succeed one another at progressively higher levels.

1 2. ln a speed-responsive centrifugal governor as in claim 11, wherein the spaces between the groups correspond to the axial dimension of the periphery of. the ring. the ring is selectively adjustable angularly to carry each space in register with a separate one of the pins, and the spaces are adequate to allow the ring to he slipped axially over the registered pins.

13. In a speed-responsivecentrifugal governor including a body having an axially extending recess in its top end, a cylindrical guide shaft rigid with the body extending axially of the recess, a cylindrical control sleeve about the guide shaft having relative axial movement, a compression spring biasing the sleeve axially upon the guide shaft inwardly of the recess, centrifugally actuable means responsive to a predetermined rotating speed of the body to slide the sleeve along the shaft out-- wardly of the recess against the bias of the spring, and-groove means extending about the surface of the guide shaft for sub stantially the length of the latter for conducting a stream of live air over the interior surface of the sleeve surrounding the guide shaft.

Claims

1. In a speed-responsive centrifugal governor including a body having an axially extending recess in its top end, a cylindrical guide shaft rigid with the body extending axially of the recess, a cylindrical control sleeve about the guide shaft having relative axial movement, a compression spring biasing the sleeve axially upon the guide shaft inwardly of the recess, centrifugally actuable means responsive to a predetermined rotating speed of the body to slide the sleeve along the shaft outwardly of the recess against the bias of the spring, and means disposed within the recess selectively operable for adjusting the tension of the spring; groove means extending about the surface of the guide shaft for substantially the length of the latter for conducting a stream of live air over the interior surface of the sleeve surrounding the guide shaft.

3. In a speed-responsive centrifugal governor as in claim 2, wherein the guide shaft has an annular shoulder overlying a bottom wall of the body and has a screw portion of reduced diameter depending through the said bottom wall adapted for internal threaded engagement with a rotor shaft.

4. In a speed-responsive centrifugal governor as in claim 1, wherein the sleeve has a normal condition under the bias of the spring in which an exit end of the groove means is blocked from communicating with the recess.

5. In a speed-responsive centrifugal governor as in claim 4, wherein bifurcations are provided in the body, and the exit end of the groove means has communication through the recess with the bifurcations following a predetermined degree of axial movement of the sleeve against the bias of the spring.

6. In a speed-responsive centrifugal governor as in claim 2, including a housing providing a chamber in which the body of the governor is disposed, the housing having a valve seat in spaced axial relation to the guide shaft and to the sleeve defining a live air inlet passage communicating with the chamber, the chamber being adapted for connection with a rotor chamber, and the sleeve being a valve having an end adapted to close upon the seat so as to block the inlet passage from the chamber as a consequence of a predetermined degree of outward movement of the sleeve.

7. In a speed-responsive centrifugal governor as in claim 1, wherein the means for adjusting the tension of the spring comprises a ring separate from the body and seated atop the spring, the ring Having a plurality of notches arranged angularly about its periphery, a plurality of pins numbering less than the number of notches projecting radially from the body in overlying relation to the ring, each pin being at the same level as the others, each pin being releasably engaged by a separate notch, each notch engaged by a pin being at the same level as the other engaged notches, the ring being tensioned by the spring in such engaged relation and being selectively subject to axial disengagement from said pins and selective angular adjustment so as to engage notches at other levels with the pins.

10. In a speed-responsive centrifugal governor including a governor body adapted at its bottom and for attachment to a rotary drive shaft and having an annular recess opening through its top end, a cylindrical slidable control member, a yieldable compression spring having one end abutting the control member and biasing it axially toward the bottom of the recess, and means responsive to centrifugal force developing during rotation of the governor body tending to move the control member axially against the bias of the spring; the improvement comprising means for selectively adjusting the degree of bias of the spring upon the control member, the adjusting means comprising a ring separate from the governor body having a central area abutting the top end of the spring, a plurality of notches having various levels formed about the periphery of the ring, a plurality of pins extending radially from the governor body at identical fixed levels in overlying relation to the ring, a separate one of the notches being in releasable pressed engagement under the force of the spring with a separate one of the pins, each notch engaged by a pin being at the same level as each of the other notches engaged by the other pins, and the ring being selectively axially releasable from the pins and selectively angularly adjustable so as to register selected notches of other levels with the pins; wherein the ring is disposed in the recess between the governor body and the control member in concentric and axially slidable relation to both.

11. In a speed-responsive centrifugal governor as in claim 10, wherein the notches are arranged in identical groups spaced angularly equally apart, the pins correspond in number to the groups and are spaced angularly equally apart, and the notches in each group succeed one another at progressively higher levels.

12. In a speed-responsive centrifugal governor as in claim 11, wherein the spaces between the groups correspond to the axial dimension of the periphery of the ring, the ring is selectively adjustable angularly to carry each space in register with a separate one of the pins, and the spaces are adequate to allow the ring to be slipped axially over the registered pins.

13. In a speed-responsive centrifugal governor including a body having an axially extending recess in its top end, a cylindrical guide shaft rigid with the body extending axially of the recess, a cylindrical control sleeve about the guide shaft having relative axial movement, a compression spring biasing the sleeve axially upon the guide shaft inwardly of the recess, centrifugally actuable means responsive to a predetermined rotating speed of the bodY to slide the sleeve along the shaft outwardly of the recess against the bias of the spring, and groove means extending about the surface of the guide shaft for substantially the length of the latter for conducting a stream of live air over the interior surface of the sleeve surrounding the guide shaft.