US2672534A - Motor-driven machine - Google Patents

Description

March 16, 1954 L. J. FAITH-ELL ET AL MOTOR-DRIVEN MACHINE Original Filed June 16, 1945 Patented Mar. 16, .y 1954 Hansson,

Stockholm,. Sweden,f. assignorsf` to Aktiebolaget Elektrolux, Stockholm, Sweden, a. corporation of vSweden Original application June` 16, 19415,'V Serial No.

599,934. Dividedand thisxapplication .December 17, 1949,.v SerialLNo. 133,552

Claims priority, applicationiSweden. August 3, 1944 6 Claims.v l

Thepresent' invention relates vto motor' driven machinery, and more particularly tomachinery hav-ingan electric motor driveand-automatic provisions for quickly interrupting the electric current upon overload of the-machinery. This application is a division of our application Serial No. 599,934led June 16, 194.5J which has :become abandoned.

In electrically drivenmachines which are vsubject to temporaryheavy overloads, it has' previously been known to protect themotor against damage from overloadby employing a centrifugalswitch which interrupts the electric current upon decrease ink the speed of rotationl of the motorshaft. However, whenv the motor shaft andthe driven shaft are connected by means of a slipping transmission, the speed of the driven shaft may decrease without any corresponding decrease in the speedof the motorshaft; thereby not affecting the switch. Consequently, the transmission means may be subjected to considerable wear vdue to slipping.

In othercases, when usingfa belt drive, a certainV degree of slipping'causes the belt to leave the pulley. This operating condition is favorable because the durationof the slipping and wear of the'belt is reduced, but,.on the'other hand, itis combined with the disadvantage that the belt must ibe put back into its place each time. Especially with motor driven apparatus and machinery for, common use; such as floor polishers' and kitchen appliances, thisk disadvantage causes muchtrouble to the operator.

It is, therefore, an object of this invention to provide an` improvement. for: protecting motor driven machinery against damage fromoverload which overcomes and obviates the foregoing disadvantages.

Further objects and advantages of the vinvention .will be apparent from the following description considered in` connection with the accompanying drawings forming part of this specification,.and of which:

Fig. l is a sectional view, taken on the line I-I of Fig..2, ofthe lower portion of a mixing machine for kitchen use illustrating an embodiment of the invention;

Fig: 2 is ya plan view of the machine, partly in sectionon line II-II of Fig. 1; and

Figs.' 3to 5 are elevation and sectional views, respectively, showing details of the machine in Figs. 1 and 2 onv an enlargedscale.

Referringto` Figs'. 1 and reference `character I designates .generally the housing and' II the base platef of" the mixing machine, the elec- 2 tric motor andigearing ofk whicharedesignated by I2 andIS, respectively. Two tools ofthe-machine, agcontainer and an agitator, are designatedby`l4 and I5. Further, IIi-designat'esfthe driving belt of the machine, I'I-the motori'pulley and I8=the pulley ofthe gearing.

In the embodiment'of 'the inventionillustrated in Figs. 1 to 5, a centrifugal relay which is adapted to interrupt the electric current ofthe motor I2 upon overload of themachine; applied to the pulley I8. This'relay comprises vtwo governor weights symmetrically pivoted Within the pulley on pins I9. Whenn the pulley rotates with an incerasing speed the'weights 20,` due to increase 'in centrifugal force,v turn or pivotabout the pins I9' to a position corresponding to the speed. Due to this movement ofthe weights, a sleeve 22, which is slidably mounted on the hub of the pulley, ispressed inwardly into the pulley and compresses a spring 23 which'tendsftopress the sleeve inwardly (upward in-Fig. 5).

When the speed and hence the centrifugal forcedecreases, the sleevek 22 moves outwardly and engages a lever 25, which in turn coacts with the control mechanism of a switch 24; The lever 25 is pivoted on a pin 26carried by a support 21 in the gear housing. This supportalso carries the switch-and the control means therefor. The switch 24' is a toggle switch, the .lever 28'of which isy arranged to be actuated'by an angle lever 30 carried by a pin 29-on the supportZ'II One-end of the angle lever 30 is provided with a handle which projects` through thev housing I 0. The lower portion of the angle lever Iliorms-a fork 3l' which guides theleveri 2lir of the switch.

Another lever 32 is also carried by thepin-29 and coacts with the angle lever 30. The lever32 is'actuatedby a torsion spring 331a1so `mounted on the-pin 29,` such spring tending to turn the lever 32 i'n a clockwise direction to the position illustrated in Fig.'- 1. By'means of a small hook 3'4 onthe lever 32, the langle level- 30 `can-.be actuated to move the lever 2'8l of theswitch to its oiposition (openposition) when'the lever- 32 is moved in thef clockwise direction just men.- tioned. Thelever 32 is arrangedl to coact with the lever 25.` A- torsion spring35ltends to press the vlever 25 against-atongue-Bof theangle-lever 30, sucl'rtongue serving to guide the-lever 25vin relation to the lever 32. I

TheA embodiment just described is` operated in 'thez` following` manner. To start theK machine, the 1 handley of" the angle lever 30 isv4 pushed down sothat thisY leverwill turn about the pin 29"in a counterclockwisek direction, as seen" in" Fig; 1',

whereby the fork 3| moves the lever 28 of the switch 24 to its on position (closed position). Simultaneously the hook 34 is engaged and the lever 32 will `also be moved in a counterclockwise direction, as seen in Fig. 1, until that lever moves to the position shown in Fig. 3. The handle of angle lever 30 is maintained in its down position for a few seconds until the motor speed picks up and the motor shaft rotates at a normal rate.

Due to rotation of the pulley I8, the outward movement of the Weights forces the sleeve 22 inwardly into the pulley hub. The lever 25 is then actuated by the spring 35 to catch and take hold of the lever 32 by a tongue 38, thereby keeping the switch in its on position (Fig. 3). If the machine becomes overloaded and the speed of the driven shaft decreases, the sleeve 22 is pushed outwardly (downward in Figs. 2 and 5) by the spring 23. The lever 25 is thus acted upon and caused to pivot a little about the pin 26, whereby the tongue 38 becomes disengaged from the lever 32. When this occurs the lever 32 is then actuated by the spring 33, and, by means of the hook 34, moves the angle lever and also the lever 28 of the switch 24 back to its oil position (Fig. 1). When the machine is stopped manually by pushing up the handle of the lever 30, the latter turns about the pin 29 independently of :the lever 32. When the speed of the driven shaft decreases to a certain suitable value, however, the lever 32 is released in the manner just described when overload occurs.

The regulator is so adjusted that the electric current will be interrupted before the belt slips off the pulley. In the event the belt should slip off, this indicates that the belt should be exchanged because it cannot transmit power efficiently due to wear.

While a single embodiment of the invention has been shown and described, it will be apparent i that modifications yand changes may be made Without departing from the spirit and scope of the invention, as pointed out in the following claims.

What is claimed is:

1.` Control mechanism comprising a manually operable part movable between operative and inoperative positions, a catch mov-able toward and from a holding position, a member movable between active and inactive positions, spring means to bias the member to its inactive position, the member being moved to its active position against the tension of the spring means responsive to manual movement of the part 'from its inoperative to its operative position, the catch in the holding position being capable of holding and retaining the member in its active position when moved thereto responsive to manual movement of the part, the spring means being operable to move the member from the active to the inactive position when the catch moves from its holding position, the part, responsive to movement of the member from the active to the inactive position, being moved from its operative to its inoperative position whenever the part at such time is in its operative position, the part also being manually movable from its operative to its inoperative position independently of the member even when the latter is retained in its active position by the catch.

2. Control mechanism for controlling the operation of apparatus comprising a manually operable part movable between operative and inoperative positions, a catch movable between holding and releasing positions, flrst spring means to bias the catch to one of its positions, the catch being adapted to be moved to its other position, against the tension of the first spring means, responsive to a condition affected by operation of the apparatus, a member movable between active and inactive positions, second spring means to bias the member to its inactive position, the member being moved to its active position against the tension of the second spring means responsive to manual movement of the part from its inoperative to its operative position, the catch in the holding position being capable of holding and retaining the member in its active position when moved thereto responsive to manual movement of the part, the second spring means being opera'ble to move the member from the active to the inactive position when the catch moves from its holding to its releasing position, the part, responsive to movement of the member from the active to the inactive position, being moved from its operative to its inoperative position whenever the part at such time is in its operative position, the part also being manually movable from its operative to its inoperative position independently of the member even when the latter is retained in its active position by the catch and the catch subsequently moves from its holding to its releasing position responsive to the condition affected by operation of the apparatus.

3. Control mechanism for controlling the operation of apparatus having a driven element, such mechanism comprising a manually operable part movable between on yand off positions, a member movable between active and inactive L, positions, spring means to bias said member to its inactive position, a movable catch adapted to move toward and from a holding position responsive to predetermined increase and decrease in speed, respectively, of the driven element, the member having a region in the path of movement of the part which is effective to move the member to its active position when the part is moved to its on position, the catch being operable to hold and retain the member in the active position when in its catch holding position, the spring means being operable to move the member from the active to the inactive position when the catch moves from its holding position, the part being contacted by the region of the member when the latter moves from the active to the inactive position to cause the part to move from the on to the off position whenever the part at such time is in its on position, the part also being manually movable from the on'to the off position independently of the member even when the latter is held and retained in its active position by the catch.

4. Control mechanism comprising a manually operable part movable between operative and inoperative positions, a pivotally mounted catch angular-ly movable toward and from a holding position, a member movable between active and inactive positions, said part and member being angularly movable with respect to one another about the same axis, torsional spring means at the vicinity of such axis to bias the member to its inactive position, the member being moved to its active position against the tension of the spring means when the part is manually moved from its inoperative to its operative position, the catch in the holding position being capable of retaining the member in its active position, the spring means being operable to move the member from the active to the inactive position thereof when the catch moves from its holding position, the

part. upon movement of the member from the active to the inactive position, being actuated to move from its yoperative to its inoperative position whenever the part at such time is in its op erative position, the part also being manualiy movable from its operative to its inoperative position independently of the member even when the latter is retained in its active position by the catch.

5. Control mechanism as set forth in claim 2 in which the catch is angularly movable about a first axis between its holding and releasing positions and. the part and the member are angularly movable with respect to one another about a second axis perpendicular to said first axis, the first spring means to bias the catch to said one position comprising a first torsion spring at the vicinity of said rst axis and the second spring means to bias the member to its inactive position comprising a second torsion spring at the vicinity of said second axis.

LARS JOHAN FAITH-ELL. ERIK OSKAR HELGE HANSSON.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 934,211 Pomeroy Sept. 14, 1909 1,044,609 Watson Nov. 19, 1912 1,047,557 Owens Dec. 17, 1912 1,263,978 Lebovici Apr. 16, 1918 1,346,067 'louchy July 6, 1920 1,559,595 Dauplaise Oct. 27, 1925 2,100,710 Dendel Nov. 30, 1937 2,472,526 Frazee June '7, 1949

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