US2136252A - Speed responsive electrical contactor - Google Patents

Description

Nov. 8, 1938. c. A. RASMUSSEN I SPEED RESPONSIVE ELECTRICAL CONTACTOR Filed larch 4, 1935 2 Sheets-Sheet 2 INVENTOR.

ATTORNEY.

Patented Nov. 8, 1938 PATENT OFFICE SPEED RESPONSIVE ELECTRICAL CONTACTOR Christian A. Rasmussen, Cleveland, Ohio Application March 4, 1935, Serial No. 9,244

10 Claims.

This invention relates to electrical contactors and more particularly to electrical contactors arranged to be driven by power and responding by the action of centrifugal force to the speed of the power source.

It is among the objects of the invention to provide:

An improved motor drivable electric switch operable responsive to speed of the motor;

An improved electric switch employing the principle of centrifugal force, to operate it;

An improved motor drivable electric switch responsive to motor speed and having improved adjustment means to adjust its response to the speed of the motor.

Other objects will be apparent to those skilled in the art to which my invention appertains.

My invention is fully disclosed in the following description taken in connection with the accompanying drawings, in which:

Fig. 1 is a longitudinal sectional view of a switch apparatus embodying my invention;

Fig. 2 is a cross-sectional view taken approximately from the plane il of Fig. 1;

Fig. 3 is a fragmentary plan View taken approximately from the plane 5 of Fig. 1;

Fig. 4 is a fragmentary view similar to a part of Fig. 1 but taken from a plane at right angles to that of Fig. 1;

Fig. 5 is a fragmentary view similar to Fig. 1 illustrating a switch device embodying my invention in another form;

Fig. 6 is a longitudinal sectional view of some of the parts of Fig. 5, the view being taken from a plane at right angles to that of Fig. 5;

Fig. 7 is a cross-sectional View taken approximately from the plane 99 of Fig. 6.

Referring to the drawings Figs. 1 to 4, at 90 is shown a housing having end members SI and 92 in which are seated ball bearings 93 and 94 rotatably supporting a shaft 95 having secured thereto a driving pulley 96 illustrated as of the grooved type but which may be of any suitable type. The shaft 95 is adapted to be rotatably driven by a belt on the pulley 96 belted to a suitable pulley on a driving motor.

A yoke 01 secured to the shaft 95 in any suitable manner such as by a screw 98, has pivoted thereto at opposite ends spaced from the shaft 95, centrifugal balls 9999 to which are pivoted at one end links I00-I00 the opposite ends of which are pivoted as at IOIIOI to a head I02.

Upon rotation of the shaft 95, the balls 9999 will move outwardly radially and will draw the head I02 toward the right as viewed in Fig. 1

against the yielding pressure of a spring I93 telescoped. on the shaft, abutting at one end upon the head I02 and at the other end upon a block I04 longitudinally adjustably secured to the shaft to vary the tension of the spring.

The head I02 has a sleeve, preferably integral therewith, upon which is press-fitted the inner raceway I06 of a ball bearing. The outer raceway I0'l of the bearing is telescoped into the annular wall of a cup-shaped element M8, the cup bottom I09 of which is perforated to encircle the shaft 95. The cup member I09 is retained in place on the outer raceway element by a sleeve I I0 telescoped over the element I00 and having a radially extending flange I I I overlapping the raceway. A bracket Il2 has one leg H3 thereof secured to the-element I00 by a screw I I4 extending through the leg H3 and through the sleeve H0 and into the element I08, the other leg H5 of the bracket being bent to extend transversely of the shaft and having a perforation encircling the shaft.

A channel-shaped element IIS has the web of the channel III encircling the shaft, and the flanges IIO of the channel extend substantially parallel to the shaft, spaced therefrom, and the outer ends thereof are bent over into feet II9 H9, and to the feet I I9 is secured a panel I of insulating material.

The feet II9 are secured to the panel by bolts I2II2I projected therethrough and the open end of the channel thus provided is stiffened by a bridging member 122 of sheet metal secured by the same bolts I2I and encircling the shaft. The panel I20 has a deep notch 235 in which are disposed the shaft and the channel legs IlB-IIB and bracket legs II2 as shown in Fig. 2, the bridging member I22 therefor also reinforcing the panel I20.

A compression spring 223 is telescoped on the shaft abutting at one end upon the leg I I5 and at the other end upon the web portion Ill of the channel. Initial tension in the spring I23, if provided, will tend to thrust the cup bottom I09 toward the left as viewed in Fig. 1 by reacting through the bracket H2 and tend to thrust the channel web III toward the right as viewed in Fig. 1, and the thrust may be taken by a washer I24 disposed between the parts II! and I09 just referred to.

The panel I20 has a pair of contacts l25-I25 thereon, secured by bolts I26 projected through the panel, the contacts being connected by a wire 4 extending across the panel. The panel is supported by the bridging member I22 on the shaft and by the web portion I I1 of the channel on the shaft.

The member 02 of the housing has a bracket I21 extending therefrom and a contact support I28 of insulating material is supported thereby and has a groove :29 therein by which the support I28 may be shifted on the bracket I21 longitudinally of the shaft and spaced therefrom. The support I28 has a slot I30 therein and a screw I3I is projected through the slot and into the bracket I21 to fix the support 23 in any longitudinally adjusted position.

Depending from the support 420 is a pair of contact fingers I32 and I33 of metal, secured to the support by screws I34 projected therein'to through the support. Each finger has a contact iii) thereon and the fingers are disposed so that the contacts 5 are opposite the contacts #25 above mentioned. Each finger has a terminal screw I35 thereon to which electric connection may be made, and the finger 232 has a wire 35 connected thereto, and the finger 533 has a wire 31 connected thereto by the screws I35. The wires and 31 are part of an electric system or circuit to be controlled.

The panel 520 has edge portions I35-I35 disposed under and adjacent to the underside of the support 23 whereby rotation of the panel when the shaft 95 rotates is prevented, the edges E30 engaging the support 23 in either direction of rotation.

In the operation of the switch device above described, when the shaft 95 is rotatably given at speed above a predetermined amount by the motor to which it is belted, the centrifugal balls 99 move outwardly radially and draw the bearings 506-551, together with the element I08 and bracket H2, toward the right as viewed in the drawings. The spring I 23 is moved along the shaft by the leg I i5 and moves with it the channel-shaped element H6 which correspondingly moves the panel 20, carrying the contacts I25 I25 with it.

By this movement, the contacts I25 are brought into engagement with the contacts 55, closing a circuit from the wire 36 through the contacts and the bridging connection 4 and out at the wire 31.

After the contacts I25 and 5 have been engaged, the balls 99 may continue to move farther outwardly, moving the bracket I2 farther toward the right as viewed in Fig. 1. Thereupon the contacts I25 and 5 will be held in resilient engagement by compression of the spring I23, the channel-shaped element I I6 being prevented from further movement by stopping of the panel I20 by the contact engagement, and the leg II5 moving toward the right, away from the panel I20, compressing the spring upon the web I !1 of the channel element IIB.

Thus the bracket I I2 may have a greater movement than the panel I20.

When the motor slows down to speeds below a predetermined speed, the shaft 05 is thereby slowed down, the balls 99 are retracted by the spring I03 and ultimately the cup bottom I09 engages the channel web I I1 (or the thrust washer I24 therebetween) and the panel I20 is moved thereby toward the left as viewed in the drawings, and ultimately engagement of the contacts 5 and I25 is broken.

In order to insure that the circuit comprising the wires 36 and 31 will be broken at a precise slowing down speed of the motor, the contacts 55 may be moved toward or from the contacts I25-I25 to vary the instant of breaking. This may be done by moving the contact support I20 along the bracket I21 adjustably and fixing its position by the screw I 3I. In any position of the contacts 55, they are insured of engagement by the contacts I25 because of the relatively greater movement of the bracket II2 than the panel I20 and the compression of the spring I23, which cushions the panel I 20.

In the embodiment of my invention illustrated in Figs. 5 to '1 inclusive, I have shown at 200 a shaft, at 20I a spring and at 202 links similar to the corresponding parts of Fig. 1, the links 202 being pivoted to a head 203 provided with a tubular portion 204 upon which is pressed the inner raceway 205 of a ball bearing having an outer raceway 200 on which is secured a ring 201.

As shown in Fig. 5, a yoke 208 is secured at one end to the ring 201, extends longitudinally along the shaft, and at a point spaced from the ring encircles the shaft. A panel 209 of insulating material is perforated as at 2I0 to admit the shaft therethrough. A plate 2| I is secured on one side of the panel 209 and a compression spring 2I2, telescoped over the shaft, abuts at one end upon the plate 2H and at the other end upon the encircling portion 2I3 of the yoke 208.

A friction washer H4 is fitted on the sleeve 204 of the head 203, abutting upon the inner raceway 205, and is adapted to be frictionally engaged by a washer 2I5 telescoped on the shaft and disposed between the washer 2 I4 and the panel 200; and by the construction illustrated and just described, it will be apparent that the two friction washers 2I5 and 2M are normally held in pressure engagement by the spring 2I2.

The plate 2I I is perforated at spaced points on opposite sides of the shaft 200, and a pair of pins 2I6-2I6 both parallel to the shaft are projected through these perforations and secured in the ring 201 and function as supports and guides for the panel 209.

The panel 209 has a pair of contacts 2I12I1 connected by a wire 54. Above the shaft 200 as viewed in Fig. 5 is a bracket 2I8 upon which is slidably adjustably mounted a support 2I9, the construction of the bracket and support preferably being similar to the bracket I21 and the support I28 described in connection with Figs. 1 to 4. Depending from the support 2 I 0 is a pair of posts 220 and 22I secured to the support by screws 232, the posts being preferably formed from insulating material.

The post 220 has a pair of contacts 56 and 55 thereon, one above the other (see Fig. '7), having portions confronting the contacts 2I1 and having portions on the opposite side of the post 220 in which connection screws 222 are provided to secure circuit wires 11 and 86 to the contacts. The post 22I likewise has a pair of contacts 223-223 supported thereby, having portions confronting the contacts 2 I1 and portions on the other side of the post for receiving screws 224, one of the screws having a wire 1I secured thereto and being connected to the other screw by a bridging wire 215.

The panel 200 has upwardly extending abutments 225 and 226 spaced from the underside of the contact support ZIS; and, by the construction above described, it will now be clear that the panel may oscillate around the shaft 200, supported by the pins 2I6 on the ball bearing, and in each direction of oscillation will be stopped by engagement of the abutments 225 and 226 with the support 219.

The stationary contacts 56 and 55 in one pair and 223223 in the other pair, are disposed so that when the panel 209 is oscillated in one direction, for example clockwise as viewed in Fig. '7, its contacts 2ll-2l1 will be confrontingly opposite the contact 55 and one of the contacts 223; and when oscillated to the limit of movement in the other direction, its contacts will be confrontingly opposite the contact 56 and the other of the contacts 223.

In the operation of the form of Figs. 5 to 7, above described, when the shaft 200 is rotated by the motor in either direction, at the instant of starting to turn, rotational movement of the head 203 will be transmitted through the pressure-engaged friction washers 2M and H5, to the panel 209, oscillating it to one or the other of its stopped positions. Continued rotation of the shaft will cause the friction washer to slip or drag one upon the other holding the panel in its stopped position. Further rotation of the shaft in speeding up will retract the head 203 against the spring 20! and draw the panel along toward the right as viewed in Figs. 5 and 6 to engage the contact 2H with contacts on the posts 220 and 22!, and thereafter will retract the head 283 still farther, removing the pressure from the friction washers and compressing the spring 2l2 and holding the contacts engaged by the spring pressure thereof and substantially without sliding friction in any of the parts, the relative rotary movement being taken in the ball bearing.

If the rotation of the shaft 20!! be clockwise as viewed in Fig. '7, the engagement of the contacts will connect the wire 86 with the wire H, and if it be in the other direction will connect the wire I1 with the wire II. When the motor slows down and the shaft 200 reduces in speed, the head 203 will be moved toward the left as viewed in the drawings and ultimately will move the panel 209, upon engagement of the friction washers, to disengage the engaged contacts.

The wires 11, 86 and II referred to are part of a circuit or system to be controlled.

The instant of breaking the contact engagement can be adjusted by adjustably moving the contact posts 220 and 221 by adjustably moving the support 219 on the bracket 2l8.

My invention is not limited to the exact details of construction of electrical switch shown and described. Many changes and modifications may be made within the spirit of my invention without sacrificing its advantages and within the scope of the appended claims.

I claim:

1. In an electric switch construction, a main support, a rotary centrifugal device on the support adapted to be driven at variable speed, and comprising a speed-responsive movable element, a pair of stationary contacts and a reciprocably movable contact supported on the frame, means causing the movable contact to move into confronting relation to one of the stationary contacts selectively in correspondence with change of rotational direction, said means comprising frictional drive means operative at rotary speeds below a predetermined speed only and the centrifugal device comprising axially movable means for moving the confronting contacts into engagement at a predetermined rotational speed.

2. In a centrifugal switch construction, a main frame, a centrifugal device on the frame comprising a rotary and axially movable element, a friction element rotatable with the rotary element, a pair of stationary contacts, an oscillatable contact support having limited oscillatory movement carrying a contact oscillatably movable therewith into confronting relation to the stationary contacts selectively, the contact support being movable axially, spring means tending to move it axially and normally holding it in frictional relation to the friction element, the parts being arranged so that upon initiation of rotation of the rotary element in one direction or the other the contact support will be frictionally driven and oscillated in the corresponding direction to selectively confront a stationary contact with the movable contact and so that upon rise of rotational speed to a predetermined value the rotational element will move axially to discontinue frictional drive and withdraw the rotary element axially and the spring means will then move the contact support to engage the confronting contacts.

3. In a switch construction, a main frame, a centrifugal device on the frame comprising a rotary and axially movable element, a ball bearing comprising inner and outer raceways, the inner raceway and a friction element rotatable with the rotary element, a pair of stationary contacts, an oscillatory contact support having limited oscillatory movement and carrying a contact oscillatably movable therewith into confronting relation to the stationary contacts selectively, the contact support being axially movably supported by the outer raceway, spring means tending to move it axially reacting on the oscillatory support and on the outer raceway and holding it in frictional relation to the friction element, the parts being arranged so. that upon initiation of rotation of the rotary element in one direction or the other, the contact support will be frictionally driven and oscillated in the corresponding direction to selectively confront a stationary contact with the movable contact and so that upon rise of rotational speed to a predetermined value the rotational element will move axially to discontinue frictional drive and withdraw the rotary element axially and the spring means will then move the contact support to engage the confronting contacts.

4. In a centrifugal electric switch, a centrifugal device comprising a rotary element movable axially at changes of rotational speed above a predetermined speed, a ball bearing comprising an inner raceway supported by the rotary ele ment, an axially extending arm supported by the outer raceway, an axially movable contact support, a spring reacting on a portion of the arm and on the contact support tending to move the contact support toward the rotary element and the rotary element normally obstructing movement thereof, a stationary contact confronting the movable contact, the parts being arranged so that uponv rotation of the device above a predetermined speed the rotary element will be withdrawn axially and axial movement of the outer raceway will be transmitted through the arm and spring to the contact support and will move it to engage the contacts and upon further increase of speed the spring will yield to cushion the contact engagement.

5. The swich construction described in claim 2 and in which the stationary contacts are adjustably movable axially to adjustably vary the said predetermined engagement speed.

6. The switch construction described in claim 3 and in which the stationary contacts are adjustably movable axially to adjustably vary the predetermined speed of contact engagement.

7. The switch construction described in claim 4 and in which the stationary contact is adjustably movable axially to adjustably vary the predetermined speed.

8. In centrifugally operated switch construction, a centrifugal device comprising a rotary shaft and an element rotatable with the shaft and movable axially thereon responsive to speed changes above a predetermined speed, a ball bearing comprising inner and outer raceways and balls thereon, the inner raceway being secured to the said rotary element, and disposed co-axially of the shaft, a contact carrying element having a perforation therein through which the shaft extends, guide means supported by the outer raceway upon which the contact carrying element may reciprocate in the axial direction, a friction element surrounding the shaft, secured to the rotary element to rotate therewith and having friction engagement with the contact carrying element, a spring surrounding the shaft and abutting at one end upon the contact carrying element on the side thereof opposite to the friction element, a hanger having a portion surrounding the shaft upon which the other end of the spring abuts and said portion being connected to the outer raceway by arms bridging opposite portions of the contact carrying element, a pair of stationary contacts, a contact on the contact carrying element, the contact carrying element being oscillatable with the outer raceway to position the said contacts in confronting relation to the stationary contacts selectively, stop means for stopping oscillation of the contact carrying element in said positions, the rotary element upon initiation of rotation thereof in either direction, driving the contact carrying element by friction of said friction element to oscillate it in one direction or the other and upon the attainment of a predetermined speed moving axially to move the stationary contact into engagement with the rotationally selected stationary contact and then withdrawing to discontinue the friction driving and spring-pressing the engaged contacts together.

9. In an electric switch construction, a main support, a rotary centrifugal device on the support adapted to be driven at variable speeds and comprising a speed-responsive movable element, a binary contact comprising a pair of contact elements, and a single contact, one contact being stationarily supported and the other reciprocably movably supported on the frame, means causing the movable one of the contacts to move to effect confronting relation between the single contact and one of the pair of contact elements selectively in correspondence with change of rotational direction, said means comprising frictional I drive means operative at rotational speeds below a predetermined speed only and the centrifugal device comprising axially movable means for moving the confronting contacts into engagement at a predetermined rotational speed.

10. In a centrifugal electric switch, a centrifugal device comprising a rotary element movable axially at changes of rotational speed above a predetermined speed, a non-rotatively supported element having thrust bearing on the rotary element and movable axially thereby, the non-rotative element comprising an axial extension, an axially movable contact support and a contact supported thereby and movable therewith, a spring reacting on a portion of the extension and on the contact support tending to move the contact support toward a portion of the non-rotatively supported element and its movement being normally obstructed thereby, a stationary contact support and a contact supported thereby confronting the movable contact, the parts being arranged so that upon rotation of the device above a predetermined speed the rotary element and the non-rotative element will be moved axially and axial movement of the non-rotative element will be transmitted through the extension and spring to the contact support and will move it to engage the contacts and upon further increase of speed the spring will yield to cushion the contact engagement.

CHRISTIAN A. RASMUSSEN.

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