US2664974A

US2664974A - Variable speed governor

Info

Publication number: US2664974A
Application number: US171671A
Authority: US
Inventors: James E Russo
Original assignee: Edwards Co Inc
Current assignee: Edwards Co Inc
Priority date: 1950-07-01
Filing date: 1950-07-01
Publication date: 1954-01-05
Anticipated expiration: 1971-01-05

Description

Jan. 5, 1954 J usso 2,664,974

VARIABLE SPEED GOVERNOR Filedjfily 1, 1950 Fig. 3

, INVENTOR. James E. Russo syy a a AT TOIRNE YS.

Patented Jan. 5, 1954 UNITED STATES PATENT OFFICE VARIABLE SPEED GOVERNOR James E. Russo, Norwalk, Conn., assignor to Edwards Company, Inc., Norwalk, Conn., a corporation of New York Claims.

This invention relates to variable speed governor devices for relatively low powered motors. More particularly, it relates to variable speed friction governor devices for spring-wound motors. Such a governor has been found to be of particular usefulness in regulating the speed of driven shafts such as those upon which code wheels in the call boxes of fire alarm systems are mounted. However, such a governor has equal usefulness in any such device when it is desired to drive any element at constant but variably adjustable rotational speed.

It is an object of the present invention to provide such a governor which is of sturdy and economical construction Which will hold the rotational speed of a shaft within extremely narrow limits of variation regardless of the variation of the amount of driving power.

It is a further object of the present invention to provide a governor for spring-wound motors which by a combination of the use of centrifugal and frictional forces positively limits the speed of rotation of a driven shaft within extremely narrow limits whether the motor is fully wound or partially wound.

It is a further object of the present invention to provide a governor for spring-wound or similar motors which will limit the rotational speed of a shaft driven by such motor within extremely narrow limits and which is easily and conveniently adjustable to a Wide range of different constant speeds.

It is a further object of the present invention to provide such a governor which is so compact in construction that it may be used in limited spaces.

Another object is to provide a speed governor construction utilizing spring parts and in which reliable protection is afiorded by simple and inexpensive means for the movable spring parts, particularly as against accidental or other distortion or stressing. Another object is to provide a governor construction which will be easy to fabricate and assemble and which is substantially foolproof in handling or in adjustment. Another object is to provide a governor subunit or subassembly which is compact and strong, well adapted to Withstand the risks of handling. Another ob ject is to provide such subassembly that can be easily and quickly assembled or incorporated into a gear train mechanism or the like. Another object is to provide such a subassembly which is capable of simplicity and ease of setting or adjustment.

Other objects and advantages will be apparent from the following description of a preferred embodiment of my invention in conjunction with the accompanying drawing and the appended claims.

In the accompanying drawings:

Fig. 1 is a front elevational view of a springwound motor incorporating a speed governor device in accordance with the present invention;

Fig. 2 is a top plan view of the motor and gov ernor of Fig. 1;

Fig. 3 is a partial cross-sectional view partially cutaway and on an enlarged scale on the line 3-3 of Fig. 2 showing the details of the governor and its mounting, but with the governor yoke rotated 90 from its position in Fig. 2;

Fig. 4 is an elevational View of the governor yoke, spring and mounting sleeve assembly; and

Fig. 5 is an end elevational view of the governor yoke and spring assembly.

Referring to Figs. 1 and 2 the motor and governor are mounted between two metallic plates which for purposes of identification may be designated front plate It and back plate lI. Members l2 and I3 are suitably attached at each of their ends respectively to front plate It and back plate I I and serve to brace and space those plates and form a rigid framework into which the various parts of the motor and governor may be fitted and suitably attached.

Driving spring I4 is attached at one end to driving spring shaft I5 and at the other end to member I2 as shown at Ma. Means for winding driving spring I4 around its shaft I5 are not shown because they may be of any suitable conventional design. Driving spring shaft I5 is rotatably mounted in appropriately formed bearing apertures in plates I0 and I I and has mounted on it gear wheel I6. Gear wheel I6 is so mounted on shaft I5 that when shaft I5 is being rotated to Wind spring I4, gear wheel I5 is free to rotate with respect to shaft I5 and therefore does not rotate with it, but gear wheel I5 is so mounted on shaft I5 that, when shaft is rotated in the opposite direction, that is, when spring It is unwinding and driving the mechanism, gear wheel I 6 rotates with shaft I5 and thus transmits power therefrom.- This may be accomplished in any well known manner commonly employed in spring-driven motors such as by a ratchet and pawl arrangement and therefore in the interest of simplicity need not be described.

Gear wheel I6 meshes with pinion I7 which is keyed to driven shaft I 8. Shaft I8 is rotatably mounted in suitable bearings formed in plates iii and II and extends through one of these plates such as II to provide a shaft upon which the device to be driven, such as code wheel I9, may be keyed in any suitable manner.

Gear wheel 29 is also keyed to driven shaft i3 and therefore rotates with it. Gear wheel 29 meshes with pinion 2| which is fixedly attached to gear wheel 22, but is free to rotate on stub shaft 23 which is fixedly mounted at one end to plate it in any suitable manner. Gear wheel 22 meshes with pinion 24 which is fixedly attached to gear wheel 25 and with that gear is rotatably mounted on driven shaft |8. Gear wheel 25 meshes with pinion 28 which is keyed to governor shaft 21.

The details of the construction and mounting of shaft 23 and governor shaft 21 may best be understood by reference to Fig. 3. Shaft 23 upon which as previously stated are rotatably mounted pinion 2| and gear wheel 22 is provided near one end with an enlarged portion 28. Rivet 29 fixedly attaches it to front plate It. The other end of shaft 23 is tapered as shown at 30 and terminates in bearing point 3| of reduced diameter which fits into a generally conically shaped and centrally positioned opening- 32 provided at one end of governor shaft 2'! for that purpose. A similar opening 33 is provided at the other end of governor shaft 21 into which bearing point 34 of the tapered end 35 of screw 36 is received. Screw 35 extends through a threaded aperture provided for that purpose in bacl; plate H and is provided with a notched head 31 to permit adjustment of screw 36. Spring washer 38 serves as a. yieldable lock washer and is provided to prevent any undesired turning of screw 36 whether by rotation of governor shaft 2'! or otherwise. It is thus seen that governor shaft 21 is supported on bearing points 3| and 34 and is free to rotate when driven through pinion 25 by gear wheel 25.

The details of construction, arrangement of parts and mounting of the governor may best be understood by reference to Figs. 4 and as well as Fig. 3. Governor yoke 39 and governor flat spring 40 are staked or otherwise firmly attached to governor bushing 4| by a washer 42 mounted on bushing 4| which may be attached to shaft 2! by set screw 43. One end of bushing 4| is internally threaded as shown at 44 and a portion of governor shaft 21 is correspondingly threaded as shown at 45 so that when set screw 43 is loosened bushing 4| may be rotated on shaft 21 and moved axially along said shaft for a purpose to be described hereinbelow. When the governor is in operation set screw 43 is tightened against governor shaft 21. Firmly attached to flat spring 40 near each of its ends are governorfi W61 11 They thus limit the forward motion at

fiyweights

46, 46. Enlarged

portions

49, 49 also event tortion of spring 40 during assembly of tn m; or removal of it from the motor.

The operation of the device is as follows:

When spring I4 is tightly wound and releas d, it rotates spring shaft I 5 and gear wheel H; which since it is meshed with pinion |7 which is keyed to shaft 3 turns that shaft and code wheel |9 or whatever device is attached thereto. Without anythin further the speed of rotation of device |9 would start at a relatively high speed and decrease as the spring runs down. In order to prevent this undesirable effect the speed of rotation of driven shaft it is controlled by the speed of rotation of governor shaft 27 through the following gear train. Gear wheel 29 also is mounted on shaft |8 and rotates with it. Since gear wheel 20 meshes with pinion 2| to which gear wheel 22 is fixed and that pinion and gear Wheel are free to rotate on shaft 23, they are also driven. In turn gear wheel 22 meshes with pinion 24 which is attached to gear wheel 25 both of which are free to rotate on shaft |8 and thus drives gear wheel 25. Gear wheel 25 in turn meshes with pinion 26 keyed to governor shaft 21. It is thus seen that governor shaft 2? as well as driven shaft I8 is driven by shaft E5 and that the relative rotational speeds of governor shaft 27 and driven shaft 28 is determined by the various ratios of the gear wheels and pinions in each driving train. Since the ratios of these gear wheels and pinions are fixed, driven shaft 8 must always rotate at a fixed ratio of the rotational speed of governor shaft 21. It follows that the speed of rotation of governor shaft 2'! controls the speed of rotation of driven shaft is.

As above stated the distance of friction members 4-8, 48 from back plate I may be adjusted by moving governor bushing 4| along governor shaft 21'. When it is desired to operate the motor at a predetermined constant speed, governor bushing 4| is adjusted and then fixed by tightening set screw 43 so that the proper distance for that speed exists between friction surfaces 48, 48 and back plate When the motor is operating centrifugal force will tend to throw

fiyweights

46, 46 out in a radial direction. Since they are attached to flat spring 40 such motion is not possible. Instead. because

weights

46, 46 are offset therefrom, fiat spring 40 will be bent so that its extremities and

fiyweights

46, 46 attached thereto Will be urged toward back plate H and

friction members

48, 48 will come into contact with and ride against the surface 0f back PM? ll, i

ratio of seven to one can be obtained with a governor designed in accordance with the present invention in which but a relative short adjustment of the governor bushing along the governor shaft, say in the order of A inch, is required where the governor flyweights are spacedabout 1 inch apart. It is to be understood that neither these dimensions nor the ratio of one of them to the other is to be interpreted by way of limitation of the present invention, but that they are set forth merely to show the compactness of a device made in accordance with the present invention capable of operating over a wide range of uniform speeds.

I claim:

1. A speed governor comprising a rotatable shaft having means for rotatably supporting it, said means including a frame plate presenting a surface at right angles to the axis of said shaft, said shaft having secured thereto a yoke having stop arms that extend radially therefrom are axially spaced from said frame plate surface, a plurality of spring arms extending radially outwardly from said shaft in the space between said yoke and said frame plate with each spring arm adjacent a yoke stop arm and with the yoke stop arms thereby respectively positioned in the path of flexing movement of the spring arms in axial direction away from said frame plate, each spring arm having a weight at its outer end with the center of mass of each weight on that side of the spring arm remote from said frame plate surface whereby upon rotation at sufficient speed said spring arms yield in axial direction away from the respective yoke stop arms and toward said frame plate, and means at the outer ends of said spring arms for making rubbing engagement with said surface in response to yielding of said spring arms as aforesaid.

2. A speed governor as claimed in claim 1 in which said yoke stop arms and said spring arms are provided with coacting parts to limit the extent to which the outer ends of the spring arms are movable in axial direction.

3. A speed governor as claimed in claim 2 in which said yoke and said spring arms are secured to said shaft by means of a bushing on the shaft, there being means securing said yoke and said spring arms to said bushing in fixed relation to each other to form a unit with said bushing, said bushing and said shaft having coacting parts for fixing the axial position of said bushing along said shaft and for thereby setting the spacing of said yoke with its stop arms and said spring arms, as a unit, from said frame plate surface.

4. A speed governor comprising a rotatable shaft having a pair of companion overlying radially extending arms of which one is rigid and the other is of spring material whereby upon flexing its outer end is axially movable relative to the outer end of its companion rigid arm, the latter limiting flexing of the spring arm in one direction, each spring arm carrying at its outer end an offset weight for flexing it in a direction away from its companion rigid arm in response to rotation at sufficient speed, means providing a surface extending at right angles to the shaft and positioned in the path of axial movement of the outer ends of said spring arms when the latter are flexed in response to sufficient speed of rotation, and means movable with said spring arms for making rubbing contact with said surface.

5. A speed governor according to claim 4 in v shaft having a pluralityof spring arms extending radially outwardly therefrom, each spring arm carrying at its outerend an offset weight for flexing it in response to rotation at sufficient speed and to thereby move its outer end in axial direction, relatively rigid means carried by said shaft and rotatable therewith and extending ra-- dially outwardly therefrom, said rigid means and said spring arms having coasting parts to limit the extent to which said outer ends of the arms are movable in axial direction, means providing a contact surface positioned in the path of axial movement of the outer ends of said spring arms, and means movable with said spring arms for making rubbing contact with said surface.

7. A speed governor comprising a rotatable shaft adapted to be mounted for rotation and carrying a bushing, said bushing having secured thereto a plurality of radially extending spring arms, each spring arm carrying at its outer end a friction contact member and an offset weight for flexing the spring arms in response to rotation to thereby effect axial movement of the friction contact member in a direction toward a plane at right angles to the shaft, said shaft and bushing having interfitting cylindrical bearing surface portions for coaxially aligning the bushing and the shaft and for permitting rela tive rotary and axial movement therebetween and having respective external and internal threaded portions which are interengaged to form a threaded connection between the shaft and the bushing to set the axial position of said bushing relative to said shaft and thereby set the distance throughout which said spring arms have to flex to bring said friction members into substantial coincidence with said plane whereby, upon rotative mounting of said shaft relative to a friction surface so that the latter and said plane are substantially coincident, said friction members can make rubbing contact with said friction surface, and threaded means for holding said bushing against rotary movement relative to said shaft.

8. A frictional speed governor comprising a rotatable shaft having secured thereto a flat spring that extends transversely of the shaft to provide two opposed radially extending flat spring arms each having an offset weight attached thereto at its outer end, a yoke carried by said shaft and extending transversely thereof and adjacent said spring arms, the latter and said spring arm having coacting parts for limiting movement of said weights in a direction substantially parallel to the axis of said shaft, said coacting parts comprising two opposed arms of said yoke that extend radially outward with their outer ends terminating respectively adjacent the outer ends of said two opposed flat spring arms whereby the outer ends of said spring arms, upon flexing in response to changes in the centrifugal forces acting upon said offset weights, move in a general axial direction toward or away from the outer ends of the opposed arms of said yoke, and friction contact members associated and movable with the outer ends of said spring arms whereby, upon assembly of said shaft relative to a friction surface positioned at right angles to the axis of said shaft, the flexing of said spring arms can move said friction contact members ascents 7 into or out of friction-producing engagement with the friction surface.

9. A speed governor for a rotatable shaft having a threaded portion and an internally threaded bushing on said shaft and in threaded connection with said threaded portion for positioning the bushing axially of said shaft, a set screw to hold said bushing on said shaft against rotational or axial movement thereof relative to said shaft, a yoke and a flat spring each having a like plurality of radially disposed arms with the outer extremities of the arms of the one respectively overlying the outer extremities of the arms of the other and with means securing said yoke and flat spring, substantially at the inner extremities of their arms, to said bushing, offset weights attached to said spring adjacent the outer extremities of its arms, said yoke having slots at the outer extremities of its arms adapted to receive said weights and permitting movement thereof in directions substantially axial to said shaft, means carried by said weights providing friction contacts, and a plate providing a surface transversely of said shaft with which said friction contacts make rubbing contact.

10. A frictional speed governor comprising a rotatable shaft and means providing a rubbing surface that extends at right angles to the axis of said shaft, said shaft having secured thereto and rotatable therewith a yoke having a plurality of radially displaced cutouts, a plurality of spring arms carried by said shaft, each extending radially outwardly with its outer end substantially juxtaposed to a cutout in said yoke, each spring arm having secured at its outer end an oiiset weight which extends transversely therefrom and through a cutout in said yoke, each weight having means engageable with said yoke to limit axial movement of its associated spring arm in a direction away from said yoke, and means providing a contact member adjacent the outer end of each spring arm for making rubbing contact with said surface.

JAMES E. RUSSO.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 652,856 McGurty July 3, 1900 1,276,367 Ide Aug. 20, 1918 1,290,712 Capps Jan. 7, 1919 1,431,377 Dean Oct. 10, 1922 1,432,927 Tomlinscn Oct. 24, 1922 2,161,207 Smith June 6, 1939 2,438,703 Kemeny Mar. 30, 1948