US2488629A - Frictionally driven switch - Google Patents

Description

Nova 22, 1949 ,A. B. KLINE FRICTIONALLY DRIVEN SWITCH 2 Shee'ts-Sheet 1 Filed July 18, 1947 INVENTOR. ,19. ,5 1 9/76 {ma Jam r TO/P/VE m Nov. 22, 1949 A. B. KLlNE FRICTIONALLY DRIVEN SWITCH 2 Sheets-Sheet Filed July 18, 1947 I INVENTOR. v7.1 :2/00/7 ,5 fC/Wm ATTORNEVJ Patented Nov. 22, 1949 UNITED STATES PATENT OFFICE 1 Claim.

This invention relates to electrical switches and more particularly to an electric switch which is adapted to be closed by the motion of a shaft with which it is operatively connected for closing a circuit to indicate that the shaft is rotating.

It is an object of this invention to provide an improved zero speed switch of the kind to be more particularly described hereinafter which is designed primarily for transferring certain mechanical motion into an electric signal. The switch may be used on electric motors having a safety switch to prevent reversing of the fields before the rotor has slowed to a safe R. P. M.

Another object of this invention is to provide a switch of this kind which is very compact and may be readily adapted to various types of work having a rotating shaft, the rotation of which is desired to be indicated through an electric circuit.

Still another object of this invention is to provide a switch of this kind which is formed of a minimum number of parts comprising a movable con-tact and an operator activated by the rotation of the shaft and frictionally connected to the shaft.

A further object of this invention is to provide a frictionally operated switch Which may be readil adapted to various uses and purposes and by its construction may be supported by any conventional means and the contacts may be readily reversed for closing a switch upon the reverse rotation of a shaft.

With the above objects in view, and others which may hereinafter more full appear, this invention consists of the novel construction, combination and arrangement of parts as will be more specifically described, and illustrated in the accompanying drawings, but it is understood that changes, variations, and modifications may be resorted to which fall within the scope of the invention as claimed.

In the drawings:

Figure l. is a top plan view, partly broken away, of a Zero speed switch constructed according to an embodiment of my invention.

Figure 2 is a vertical section, taken on the line 22 of Figure 1.

Figure 3 is a top plan view of the housing with the switch and cover removed.

Figure 4 is a side elevation, partly broken away of the shaft and one clutch plate removed from the housing.

Figure 5 is a top plan view of the switch operator and clutch plate removed from the assembly.

Figure 6 is a side elevation of the fixed contact.

Figure 7 is a side elevation of the spring pressed movable contact removed from the switch.

Figure 8 is a top plan view of the inner contact insulating block.

Figure 9 is a side elevation of collar.

the shaft securing 2 Referring to the drawings, the numeral H] designates generally a zero speed indicating switch which is adapted to be moved into circuit closing position upon rotation of a shaft and biased into circuit breaking position when the shaft is stopped. Various types of electric circuits may be connected to the terminals such as a light circuit for indicating that the shaft is rotating or a timing circuit for measuring the time interval during which the shaft is rotating.

The switch i ii is formed of a cylindrical housing II open at one end, as at E2, and having an end wall i i. The end wall is is of considerable thickness for providing for a shaft bearing therethrough. The end wall I4 is formed with an opening l5 therethrough and a liquid sealing bushing or hearing I6 is fit into the opening. The opening I55 and bearing A6 are concentric to the open end I2 and co-axial with the length of the housing ll. The bushing i6 is preferably an Oilite bushing for providing suitable lubrication for the rotating shaft extending therethrough while securing the shaft sealedly in the housing II. .An operating or driving shaft ll rotatably engages through the bushing l6 into the housing I I and extends downwardly or outwardly therefrom. The shaft I1 is adapted to be connected by any suitable connecting means to a shaft or wheel whose rotation it is desired to have indicated or measured by an electric circuit controlled by the switch II). The bearing H5 is flush with the inner surface of the wall it and extends outwardly from the outer surface thereof.

One annular clutch plate I8 is fixed to or formed on the inner end of the shaft i1 and is adapted to be disposed within the housing E i The clutch plate I8 abuts the inner surface of the wall M to hold the shaft I! from sliding outwardly through the bushing l6. An annular clamping sleeve I9 is adapted to he slid on the outer end of the shaft I! for restraining the shaft from sliding inwardly of the bushing iii and housing H. The sleeve I9 is provided with a radially extending threaded opening Zll therethrough within which a set screw 2! is adapted to engage for securely clamping the sleeve I9 on the shaft ii.

The inner end of the shaft I! is formed with a threaded counterbore therethrough and concentrically through the clutch plate or disc 58.

A bolt 22 is engageable in the threaded opening on the end of the shaft for attaching the innermost driving clutch plate 24 on the shaft I l. The two clutch plates l8 and 24 are spaced apart by a spacer or washer 25 therebetween and about the bolt 22.

A cover 26 is provided for the open end 12 of the housing and is adapted to be secured thereto by bolts or screws 21 which engage therethrough and into the annular side walls of the housing I I. A sealing member or gasket 28 is clamped between 3 the cover 26 and housing II for sealing the connection therebetween.

The switch contacts of the switch H] are carried by the cover 26 so that they may be removed as a unit from the housing for necessary repairs or adjustments or reversal of the contact positions. Enlarged openings are provided through the cover 26 and the terminal bolts 29 loosely engage therethrough. The bolts 29 are sealed, and insulated from the cover 26 on the upper surface by an outer rectangular insulating bar 30. Anarcuate or semi-circular insulating member 3|, formed with openings 32 therethrough, is provided for insulating the lower ends of the bolts 29 from the cover 26 and housing The heads 34 of the bolts 29 are disposed downwardly within the housing II and nuts 35 secure the bolts 29 fixedly on the cover. A second nut 36 is carried by the upper or outer end of the bolts 29 to provide a means of attaching a circuit wire to the terminal posts 29. The bolts 29 are disposed within the housing H in a radially offset position, both of the bolts being the same distance from the center so that they may be interchanged when the shaft rotation is reversed.

A fixed switch contact member 31 is secured to one of the blots or terminals 29 within the housing The contact 31 is formed of a pair of overlapping L-shaped strips of metal. The inner strip 38 is preferably made of copper and the outer or contacting strip 39 is made preferably of tungsten or other high grade conducting mate-- rial. The horizontal arm of the contact 31 is formed with an opening 40 through which the bolt 29 is adapted to engage. The vertical arm of the contact 31 forms the contacting surface and is disposed at an oblique angle to the length of the horizontal arm so that the contacting surface may be substantially coplanar with a radius extended from the other bolt 29 so that the two contacting surfaces may engage along their entire area.

A resilient movable contact 4| is carried by the other bolt 29 for engagement with the fixed contact 37. An elongated strip of spring metal 42 is soldered, or otherwise fixed in the slot of the bolt 29 and extends across the housing A pair of tungsten contact points 44 are fixed on opposite sides of the strip 42 and are adapted to engage the fixed contact 31. The contacts 31 and 4| are normally open, being biased open by the resilient strip 42. The gap between the contacts may be adjusted by loosening the nut 35 on the bolt 29 of the movable contact and setting the gap to the desired position.

For moving the movable contact 4| into engagement with the fixed contact 3'1 when the shaft IT is rotated, an operator 45 is frictionally carried by the shaft |1 within the housing I. The operator 45 comprises a block 49 fixedly carried by a driven clutch plate 41. The driven clutch plate 41 is disposed loosely about the spacer 25 between the driving clutch plates I8 and 24 and is adapted to be urged to rotation with the driving plates by oil contained within the housing.

The block 46 is formed of a pair of fibre or insulating strips 48 fixed on a radially extending upwardly bent arm 49 on the periphery of the plate 41 outwardly of the upper driving clutch plate 24. A screw 50 engages through the arm 49 into the strips 48 and is sealed or locked against turning by solder connecting the head of the screw 50 to the arm 49.

In the use and operation of this switch If], rotation of the shaft I1, through the driving clutch plates or disks l8 and 24 will urge the driven plate 41 in the direction of rotation. The clutch will then urge the block 46 against the rear side of the movable contact member 4| pressing the contacts 4| and 31 into engagement for completing an electric circuit through the terminals 29. When the shaft ceases to rotate, the spring arm 42 will separate the contacts, thus opening a circuit.

From the arrangement of the bolts 29, it is seen that they may be interchanged for closing a circuit upon reverse rotation of the shaft l1.

Having thus described my invention, what I claim is:

In a rotation-indicating or zero speed switch comprising a cylindrical casing having an oilcontaining interior chamber and a bearing extending axially through one end of the housing, a shaft extending rotatably through said bearing with the outer end thereof exposed exteriorly of said housing, a movable contact operator in the interior chamber, a stationary contact projecting into the latter, a resilient contact in said interior chamber having a contact portion movable toward the stationary contact and disposed in the path of movement of the movable contact operator, the features which include a substantially fiat bottom in said interior chamber, a disk rigidly mounted upon the inner end of said shaft and resting rotatably on the fiat bottom and the inner end of said bearing in said interior chamber, the upper end of said cylindrical housing being open, a cover secured upon the upper open end of said housing and closing the interior chamber therein, pair of insulated binding posts spaced apart and secured to the cover and both extending through the latter into said interior chamber, one binding post supporting the stationary contact and the other supporting the resilient contact With-- in said chamber, the inner end of the shaft hav ing a threaded axial bore therein, a clutch plate secured to said movable contact operator at an angle thereto and freely overlying the upper surface of said disk, the clutch plate having a central opening concentric with the axis of said shaft and the disk thereon, a tubular spacer upon said disk within the central opening in said clutch plate, a second disk concentric with the first disk having a central opening and resting upon the spacer above said clutch plate, and a headed screw fittin into the threaded bore in the inner end of said shaft and extending through the tubular spacer and the second disk with the head of said screw retaining the latter disk in position upon said spacer.

ADDISON B. KLINE.

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

UNITED STATES PATENTS Number Name Date 740,547 Fiske Oct. 6, 1903 1,161,932 Du Bois Nov. 30, 1915 1,947,332 Christen Feb. 13, 193i FOREIGN PATENTS Number Country Date 523,983 Germany Apr. 30, 1931

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