US2610269A

US2610269A - Governor switch mechanism

Info

Publication number: US2610269A
Application number: US146575A
Authority: US
Inventors: Walter Van Guilder
Original assignee: General Mills Inc
Current assignee: General Mills Inc
Priority date: 1950-02-27
Filing date: 1950-02-27
Publication date: 1952-09-09
Anticipated expiration: 1969-09-09

Description

p 9, w. VAN GUILDER GOVERNOR SWITCH MECHANISM Filed Feb. 27, 1950 2 SHEETS SHEET l WVEWTOTR' WALTER VAN GUILDER sy W ATTORNEY Se t. 9, 1952 w. VAN GUILDER 2,610,269

GOVERNOR SWITCH MECHANISM Filed Feb. 27, 1950 2 SHEETSSHEET 2 INVENTOR- WALTER VAN QSUILDER ATTORNEY Patented Sept. 9, 1952 UNITED STATES PATENT UFFICE GOVERNOR SWITCH MECHANISM Walter Van Guilder, River Forest, 111., assignor to General Mills, Inc., a corporation of Delaware Application February 27, 1950, Serial No. 146,575

12 Claims.

This application relates to improved speed control mechanism for a rotating shaft, and more particularly to improved governor switch mechanism for use in a household food mixer or other appliance. combination oi working parts in a governor 01' Many constructions have been proposed in the speed control mechanism. past for controlling the energization of a power Other objects and advantages will be apparent source, such as an electric motor, in order to from the following specification in which a premaintain the speed of rotation of a power or ferre-d embodiment of the invention is described. motor shaft at the desired point. Such control In the drawings forming a part of this applidevices have generally been constructed in one oi cation, two types. In the first type, centrifugally dis Figure l is a schematic perspective View (with placeable members have been mounted directly certain portions broken away and other parts on the rotating shaft to be controlled and the shown only in dotted outline for clearness) of a particular electric switch mechanism designed l5 portion of a household food mixer embodying to effect the control has also been mounted on speed control mechanism acccording to the inone of the rotating parts. Such an arrangement vention. necessitates the use of brushes and collector Fig. 2 is apartial side view, with certain porrings' to complete the electrical circuit between tions broken away, showing details of the cou the switch contacts on the rotating shaft and pling between the movable governor member on the stationary parts of the motor circuit. the motor shaft and the independently mounted In the second type of construction a relatively speed control member. displaceable governor member on the motor shaft Fig. 3 is a partial top view of the governor has engaged directly against a movable speed mechanism of Figsland 2, and control member mounted on an adjacent sta- Fig. 4 is a sectional View on the line 4-4 of tionary part. In this case the separately mount- Fig. 3. ed speed control member is utilized to control the As shown in the drawings, the invention has desired switch contacts. In this type of 0011- been illustrated in connection with a household struction there has been the definite problem of food mixer which includes a casing it on which securing efficient mechanical coupling between a suitable beater i2 is supported. In the presthe governor member on the motor shaft and out case the shaft is of beater i2 is coupled in the separately mounted speed control member, driving engagement with a planetary shaft 18 without at the same time encountering the disrotatably mounted in an offset position on the advantages of undesirable friction and wear of planetary head l8 carried by vertical shaft Hi. the parts, particularly where the shaft is designed Shaft i9 is supported in bearings 26 in the casfor h h speed operation. ing 40. A pinion 2! on the beater drive shaft With these pl'oblems 0f the prior art n mind, it engages a fixedinternally toothed gear 22 in it is accordingly one object of the present inthe Casing to provide the desired rotation f veniion to provifie an improved governor or Speed beater I2 while the beater shaft i4 also revolves comm} mechatuslny w around the axis of shaft [9.

Arimher F 15 plovmon of spee d Shaft I9 is operatively connected to theshaft cortmol mecitamsm. lor ,matable shaft m 24 of a suitable electric motor or similar power WhlCh a relatively chsplaceable governor member c0 r 26 1 n 1 t1 on the rotating shaft is magnetically coupled to i Ce ma 3 i 9 an independently mounted speed control member W.h11e mi nechamtzal couphngmay adjacent the shaft 7 be provided between the parts, Fig. 1 showssche- A still further object is the provision ofa govt y and dotted Outline the preview of ernor mechanism in which a displaceable mema Sultabl? Worm 23 on 13119 motor Shaft cooperatber on the rotating shaft is effectively coupled mg w a a 39011 n' m d shaft t an independentl mounted Speed Control Gears '28 and 3t are housed within a suitable her without actual physical contact or friction s r asi 3 above h m t r d W h n t betw en th a t main casing I 9 of the mixer. Shaft 32 in turn A further object is the provision of an'imcarr es a worm 3.4 indriving engagement with proved governor mechanism embodying magnetic a further gear 36 on shaft i9. Thus the rotation coupling between the parts and in which the structural arrangement and location of the parts contribute to the eiliciency and ease of construc-- tion of the device.

Another object is the provision of an improved of motor shaft 24 is transmitted, with suitable 3 speed reduction, to the main shaft I9 of the planetary head.

The motor shaft 24 in this instance constitutes the rotatable shaft, the speed of which is to be controlled according to the present invention. On this shaft a governor member 38 is mounted for relative displacement in accordance with the different speeds of rotation of the shaft. In the preferred form of the invention, this governor member 38 is designed for relative axial movement along the shaft in response to changes in speed. For this purpose the governor member 38 is carried by radial arms 48 to which it is fastened by screws 4| (Fig. 2). As shown in Fig. l, the outer ends of the arms 48 are connected to the governor weights 42. The weights 42 are further connected by additional arms 43 to a collar 44 which rotates with motor shaft 24 and is fixed longitudinally with respect to the shaft.

In this standard type of governor arrangement, the weights 42 tend to move radially outwardly as the speed of rotation of shaft 24 is increased. This outward movement of the weights 42 then draws the governor member 38 axially down toward the fixed collar 44 on shaft 24. The governor arms 48 are spring biased so that as the speed is reduced, the governor member 38 is resiliently urged back up along the shaft to its normal or rest position.

A first speed control member designated generally at 48 is independently mounted near the motor shaft and governor member in the following manner. In its preferred form the first speed control member 48 includes a base portion 58 located close to the governor member 38 and two

legs

52 and 54, respectively, extending from the base portion on each side of the motor shaft 24. Thus the speed control member is substantially U-shaped. The ends of

legs

52 and 54 are downwardly offset as shown at 56 and 58 and terminate in

portions

68 and 62, respectively, which are parallel to but spaced slightly below the main portions of the legs. These

end portions

68 and 82 are Provided with

half bearing portions

84 and 88 for engagement with a supporting shaft 68. Shaft 68 in turn is mounted on a supporting bracket I8 which has upwardly turned lugs or ear I2 and I4 provided with openings through which shaft 68 passes. tened by means of screws I6 to the fiat top portion I8 of the motor and governor casing or to any desired supporting portion within the casing I8. Above the casing I8 the central portion is extended or projected as shown at I9 (Fig. 3) to enclose the governor member 38. One side of this upwardly projecting casing portion I9, however, is, left open as shown at 81 (Fig. 3) so that one edge of the governor member 38 may project in operative relation toward the base of the U-shaped speed control member 48.

As shown in Figs. 1-3, inclusive, the axis of supporting shaft 68 for speed control member 48 is spaced a substantial distance away from motor shaft 24. This pivotal axis also liesin a plane which is substantially. perpendicular to the motor shaft, this plane being indicated by the line 8888 in Fig. 2. The purpose and advantages of this particular arrangement of the pivotal axis of speed control member 48 will be described below.

Mounted on the first speed control member 48 is a second speed control member designated generally at 82. This second speed control member or contact arm 82 includes a base portion 84 and The bracket 18 is faslegs 88 and 88 projecting on each side of the motor shaft. Thus the second speed control member or contact arm 82 is also substantially U-shaped and has its base portion and legs located parallel to and just below the corresponding portions of the first speed control member 48. The ends of

legs

86 and 88 are riveted at 89 and 98 to the lower surface of the

respective ends

68 and 82 of the speed control member. These ends of the contact arm 82 are also provided with corresponding half bearing portions 92 which cooperate with the bearing

portions

64 and 68 of the first speed control member to constitute a complete clamp or bearing area for engagement with shaft 88 to support the two speed control members. Member 48 is relatively rigid, while speed control member 82 is somewhat resilient, so that it can be flexed relatively to member 48. In practical effect, however, both speed control members may be regarded as pivotally mounted on the common shaft or axis 68.

In order that the relative axial displacement of the governor member 38 on shaft 24 may be transmitted to the second speed control member or contact arm 82, a magnetic drive connection has been provided according to the present-invention. Thus at the base portion 84 of the speed control member 82 there is a downwardly offset supporting portion 94 joined to the rest of the base portion 84 by shoulders 98.

Portions

94 and 88 constitute a supporting seat for a small permanent magnet 88 having poles I88 directed inwardly toward the governor member 38. The inner ends of these poles are tapered as shown at I82 to provide relatively narrow vertical faces I84. Immediately opposite the narrow faces or ends I84 of the magnet poles I88, the governor member 38 has a projecting annular portion I88 of good magnetic permeability and low retentivity, which has a vertical rim I88 of substantially the same vertical thickness as the vertical thickness of the pole faces I84. As indicated in Fig. 3, the pole faces I84 are also arcuately shaped in a transverse plane, to correspond to the curvature of the rim I88 of the annular governor portion I88.

As illustrated in Fig. 2, the arrangement and operation of this portion of the mechanism are as follows: Governor member 88 is shown in Fig. 2 in its normal or rest position, i. e., the position which it occupies when shaft 24 is stationary.

The magnet pole faces I84 are attracted to the rim I88 of the governor member 38 due to the magnetic permeability of the material from which the rim portion is made. Thus the magnet 98, together with its contact arm or speed control member 82, tends to assume a position in which the magnet is at the closest possible point to the rim I88. This position is. illustrated in Fig. 2. Upon the start of rotation of shaft 24 and the gradual increase in speed of rotation of the shaft, the governor member 38 will move axially downwardly as already described, so that the rim I88 of the governor member will move along the path II8 parallel to the axis of shaft 24. Because of the attraction between the pole faces I84 and the rim portion I88, the magnet 88 will tend to follow the control member. Since the speed control member 82 is, in effect, pivoted at the axis of supporting shaft 88, the magnet pole faces I84 will follow a slightly arcuate path as indicated by the dotted line I I2.

. By location of the axis 68 a substantial distance away from shaft 24, the arcuate path IIZ can be made substantially flat so that speed 5, control member 82- and its magnet 98 can move vertically through a relatively large distance corresponding to the relative displacement of the governor member 38, without critical variations in the air gap between the pole faces I04 and the annular magnetic rim I08. With the initial location of the parts as shown in Fig. 2, the air gap will of course increase slightly as the shaft begins to rotate. As the speed of the shaft 24 is increased, the air gap will reach a maximum at some intermediate speed of the shaft, i. e., where the rim of the governor member reaches the plane 80--00 of axis 68. As the speed increases to a still greater extent, the air gap tends to be reduced slightly.

Obviously the width of this air gap, and the relative spacing of axis 60 from the shaft 24 must be so chosen that the air gap will never be reduced to zero, i. e., the magnet must never come indirect contact with the rim I08, at any point within the operating range of displacement of the governor member 38. Thus the use of a magnetic drive as the sole connection between the governor member 38 and the speed control member 82 provides a construction in which the relative displacement of the governor member can be transmitted to the speed control member with maximum efliciency, but without actual physical engagement between the parts which would cause friction or wear.

While any desired mechanism may be utilized to control the motor shaft speed in accordance with the relative displacement of the governor member 38 and control member 82, the use of an electric switch for this purpose is preferred. This switch includes contacts H4 and II8 located on the respective first and second

speed control members

48 and 82. These contacts are carried by brackets H8 and I20 supported on the speed control members at the points where the base of each U-shaped member joins the

legs

52 and 86. Contact brackets II8 and I20 are connected to leads I22 and I24 by terminals I26 and I28, respectively. These contact brackets are supported on the speed control members by rivets I30 and are suitably insulated from the rivets and from the speed control members by intermediate layers of electrically non-conducting material.

As shown in Fig. 4, three layers of insulation are provided at each point of connection and are designated I34, I36, and I38, respectively. Layers I34 and I36 are located on opposite sides of the contact bracket II8 and protect the bracket from engagement with either the speed control member 48 or the head of the rivet I30. The additional insulation layer I38 on the lower side of speed control member 48 assists in positioning the contact bracket II8 and prevents electrical contact with it.

The bracket II3 has a relatively large opening I40 at the point through which rivet I30 passes,

so that there will be no possibility of electrical out operation of the mechanism. Since a similar construction is used for the contact bracket I20 and its support on speed control member 82, the details of construction need not be repeated.

In order that the operating speed at which the switch contacts H4 and H6 will disengage may be predetermined, suitable means are provided for adjusting the initial position of speed control member 48. These means include a resilient member biasing the speed control member in one direction axially of the shaft in combination with an adjustable stop limiting the relative movement in that direction. The resilient member consists of a flat spring I46 engaging the lower surface of one leg 54 of the first speed control member 48 and urging the member 48 resiliently upwardly as illustrated in Fig. 1. This spring member I is riveted or otherwise fastened at I43 to the top of the motor casing 26, or to a suitable bracket or ledge in the casing I0. The base portion 50 of the first speed control member 48 includes a projection I5I which is engaged by an adjustable stop I52. This stop is shown in the form of a screw which is threaded in a supporting portion I54 of a longitudinally extending bracket member I56. The actual position of screw I52 may be adjusted for factory or manufacturing purposes by a lock nut I53.

The member I55 is pivoted at I58 and I60 to suitable portions of a longitudinally extending slide I62. The location and orientation of pivots I58 and I60 are such that the main body portion of member I56 is slightly angularly disposed longitudinally with respect to the slide I62.

A manual operating member I64 having a finger piece I66 and a cam surface I63 is mounted on slide I62 and engages the edge of member I56 to rock it about its pivots I58 and I60 upon longitudinal movement of the finger piece I88. This rotation of the member I56 on its pivots I58 and I60 will cause vertical movement of the bearing portion I54 and the screw or stop I52, to predetermine the position of the speed control member 48 which is held against the stop by spring I46. This portion of the control mechanism for predetermining the position of stop I52 is similar to that shown and claimed in my prior copending application, Serial No. 136,572, filed January 3, 1950. Obviously any other form of adjustable stop could be utilized with the present invention to predetermine the position of speed control member 48.

The operating member I64 includes a projection I10 for engagement with a lever arm I12 on a switch supportin bracket I14 pivoted at I16 to a supporting frame I18. A liquid contact switch I on the pivoted bracket I14 serves as an onoff switch for the motor 26, to which it is connected by suitable leads I82 and I84.

Operation of the present device will be apparent from the foregoing description. Adjustment of the finger piece I66 will determine the vertical position of adjustable stop I52. This in turn will predetermine the position of the relatively rigid speed control member 48 and its contact II4. By the same token, it will also predetermine the initial position of the second speed control member or resilient contact arm 82 which is normally biased upwardly toward the first speed control member with contact IIS against contact I I4. Upon energization of the motor circuit and increase in speed of shaft 24, the governor member 38 will be drawn axially downwardly until it reaches a point where its annular rim I08 is opposite the pole faces I04 of magnet 98. Further increase in speed of the motor shaft 24 will then result in downward movement of the magnet 98 and speed control member .82 and will thus move the contact H6 away from contact I [4 to break the circuit.

- This separation of the contacts H4 and I16 is utilized in any desired fashion to control the motor speed as, for example, by cutting an additional resistance'into the motor circuit. As the speed of shaft 24 then decreases slightly, the governor member 38 can move upwardly and the magnet 98 will followthis movement and permit the resilience of member 82 to reclose the switch contacts H4 and I 16. Thus the motor will operate at a predetermined speed determined by the initial adjustment of the speed control member 48 and its contact I [4.

The construction described above accomplishes the objects of the present invention and has the advantages of efiicient operation, absence of friction and wear of the parts, and relative simplicity of construction.

Since minor variations and changes in the exact details of construction will be apparent to persons skilled in this field, it is intended that this invention shall cover all such changes and modifications as fall within the spirit and scope of the attached claims.

Now, therefore, I claim:

1. Governor mechanism comprising a shaft rotatable at different speeds, an annular collar of magnetically permeable material of low retentivity concentrically mounted on the shaft and movable axially thereof in response to changes in the speed of rotation of the shaft, a speed control member independently mounted adjacent the shaft for movement substantially parallel to and coextensive with the range of movement of the collar, means for manual adjustment of the speed control member along said range of movement, a contact arm mounted on the speed control member for relative movement along said range parallel to said shaft, a magnet mounted on the contact arm and having its poles opposite the collar, movement of the collar in response to changes in shaft speed causing corresponding movement of the magnet and contact arm, and a switch having first and second contacts, one of which is located on the contact arm while the other is located on the control member.

2. Governor mechanism according to claim 1 in which the speed control member includes parallel legs on opposite sides of the shaft pivoted at one end on a common axis which is spaced from the shaft and which lies in a plane perpendicular to the shaft with a base portion joining the other ends of the legs on the side of the shaft opposite said axis, and the contact arm includes a similarly oriented base portion and a pair of legs the ends of which are secured to the legs of the control member near said axis, the magnet being mounted on the base portion of the contact arm.

3. Governor mechanism according to claim 2 in which the contact arm is resiliently biased toward the control member, and said means for adjustment of the control member includes a manually adjustable stop on the side of the control member opposite the contact arm, and means resiliently biasing the control member against the stop. W r

4. Governor mechanism comprising a shaft rotatable at different speeds, an annular collar of magnetically permeable material concentrically mpunted on the shaft and movable axially thereof in response to changes in the speed of rotation of the shaft, a speed control member independently mounted adjacent the shaft for movement substantially parallel to and coextensive with the range of movement of the collar, a magnet mounted on the speed control member and having its poles located opposite the collar, movement of the collar axially of the shaft in response to changes in shaft speed causing corresponding movement of the control member substantially parallel to the shaft, and a switch having a first contact mounted on the control member for movement therewith, a second contact, and means for relative manual adjustment of the second contact with respect to the shaft in a direction parallel to the shaft.

5. Governor mechanism comprising a shaft rotatable at different speeds, a governor member of magnetically permeable material mounted on the shaft and movable axially of the shaft in response to changes in the speed of rotation of the shaft, a speed control member independently mounted adjacent the shaft for movement substantially parallel to said shaft, and a magnet mounted on the speed control member and having its poles closely adjacent the governor member, movement of the governor axially of the shaft in response to changes in shaft speed causing corresponding movement of the control member parallel to the shaft to effect the desired control.

6. Governor mechanism according to claim 5 in which the control member includes a base portion extending transversely of the shaft adjacent the governor member and a pair of legs extending from the base member, one on each side of the shaft, the ends of the legs being pivoted on a common axis spaced beyond the shaft and lying in a plane perpendicular to the shaft, the magnet being located on the base portion.

7. Governor mechanism according to claim 6 in which the magnet poles are spaced from each other in a direction parallel to said common axis, and the governor member includes an annular rim immediately adjacent the poles.

8. Governor mechanism comprising a shaft rotatable at different speeds, a governor member mounted on the shaft for relative displacement in a predetermined path relative to the shaft in response to changes in shaft speed, a speed control member independently mounted adjacent the shaft and governor member for movement substantially parallel to said'path, and magnetic drive means constituting the sole driving connection between the governor and speed control members and actuating the speed control member in direct dependence on the shaft speed and in the same direction'as the resulting displacement of the governor member.

9. Governor mechanism according to claim '8 in which the governor member is mounted for relative axial displacement on the shaft.

10. Governor mechanism according to claim 9 in which the speed control member'is U-shaped, with the legs of the U extending on opposite sides of the shaft and pivoted on an axis spaced from the shaft and lying in a plane perpendicular to the shaft, and with the base of the U adjacent the governor member and on the opposite side of the shaft from said axis, the magnetic drive means being located between the base of the U and the governor member.

11. Governor switch mechanism'comprising a shaft rotatable at different speeds, a governor member mounted on the shaft for relative displacement in a predetermined path with respect to the shaft in response to changes in shaft speed, a speed control member mounted adjacent the shaft and governor member for movement substantially parallel to said path, switch contacts controlled by movement of the speed control member, and magnetic drive means constituting the sole driving connection between said governor and speed control members and actuating the speed control member and at least one switch contact in direct dependence on the relative displacement of the governor member and in the same direction.

12. Governor mechanism comprising a shaft rotatable at different speeds, a governor member mounted on the shaft for relative displacement along a predetermined path in response to different shaft speeds, a speed control member independently mounted adjacent the shaft for movement substantially parallel to the path of said relative displacement, one of said members 20 having a magnetically permeable portion and the other having magnetic means cooperating with 10 said portion but spaced slightly therefrom to constitute the sole driving connection between the members, said magnetic driving connection effectively moving the speed control member along said path in the same direction as the governor member in response to changes in shaft speed, a pair of switch contacts, the position of one of which is controlled by the position of the control member, and means for manual adjustment of the position of the other contact to predetermine the shaft speed at which the switch will operate.

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

UNITED STATES PATENTS Number Name Date 2,215,294 Morrill Sept. 17, 1940 2,254,709 Pepper Sept. 2, 1941