US2558098A - Operating mechanism - Google Patents

Description

June 26, 1951 w. PENNOW 2,558,098

OPERATING MECHANISM Filed May 19, 1945 I I 2 Sheets-Sheet 1 WITNESSES: INVENTOR 62.4 m/x/s/ pennaw.

June 1951 w. A. PENNOW 2,558,098

OPERATING MECHANISM Filed May 19, 1945 2 Sheets-Sheet 2 fig 2 Fig". 3.

lull. "IL!" INVENTOR M///. 5 Penn arv.

W7 I I o ATTOR EY Patented June 26, I951 UNITED STATES PATENT OFFICE OPERATING MECHANISM Willis A. Pennow, Cleveland, Ohio, assignor'to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application May 19, 1945, Serial No. 594,633

4 Claims. 1

My invention relates, generally, to operating mechanisms and, more particularly, to a motor actuating mechanism or unit for operating the signalling shutter of a Searchlight or any other device having fixed operating limits of movement or travel.

Heretofore it has been the practice to operate signalling shutters on searchlights by means of several different types of operating mechanisms, the most common being a solenoid and leverage mechanism and a direct-current motor mechanism wherein the motor is provided with flexible leads instead of a commutator and arranged to rotate through an angle of 90 only.

Both of these mechanisms have disadvantages for this kind of an application. The solenoid and leverage mechanism is large and cumbersome to apply, requires a relatively high current, and is relatively slow in action. The direct-current motor mechanism requires a comparatively large motor in order to provide sufficient torque on the shutter drive shaft. In general, these devices are both relatively slow in operation and do not have a long operating life.

Attempts to use motors of the commutator type for driving mechanisms of this kind have been avoided heretofore because of the necessity for always starting the motor on the same commutator segments, causing excessive burning of the segments.

Accordingly, it is an object of my invention, generally stated, to provide an improved operating mechanism for signalling shutters and the like which shall be of simple and rugged construction, economical to manufacture, and which shall function to positively drive the shutter in such manner as to effect a faster opening and closing operation thereof than heretofore obtainable.

A more specific object of my invention is to provide for using a motor of the commutator type in an operating mechanism of the character described.

Another object of my invention is to provide an operating mechanism for signalling shutters and the like wherein a slip clutch is employed so that a motor of the commutator type may be successfully used.

A further object of my invention is to utilize in an operating mechanism of the character described a gear reduction and slip clutch mechanism so that the relatively small motor of the.

commutator type may be used to operate the shutter or any other device which has definite limits of travel.

A further object of my invention is to provide an operating mechanism of the character described which permits of either manual or motor operation of the shutter or other device that it drives, and which provides for positively locking the shutter or other device in either one of two operating positions.

These and other objects of my invention will become more apparent from the following detailed description when read in conjunction with the drawing, wherein:

Figure 1 is a front elevational view showing a Searchlight of the type for which my operating mechanism is particularly adapted.

Fig. 2 is a side view in elevation, partly in section, showing how the operating mechanism of my invention may be applied to the signalling shutter mechanism of the Searchlight of Fig. 1;

Fig. 3 is a plan view in section of the operating mechanism of Fig. 2 showing the structural details thereof; and

Fig. 4 is a partial view of the hub end of the operating handle.

Referring to Fig. 1, there is shown a searchlight of the signalling type having a shutter mechanism, indicated generally at ID, of the Venetian-blind type. It will be understood that this shutter comprises a plurality of blade members disposed in parallel relation in a common plane and pivotally or rotatably mounted so that the blades may be actuated between open and closed positions.

As shown, the signalling shutter mechanism I0 is mounted at the front of the searchlight drum in order that it may be utilized for controlling the light projected by the Searchlight in a well known manner.

While my invention is particularly adapted for use in the operation of signalling shutters of this kind, it is to be understood that it may also be utilized for driving devices of other kinds which operate between fixed limits of travel.

Referring now to Fig. '2, this view shows the manner in which the operating mechanism of my invention may be utilized in operating the signalling shutter of the Searchlight of Fig. 1. In this view, only a small portion of the shutter mechanism of the Searchlight is shown. This portion is the gear train comprising a main drive gear I l and two additional gears l2 and I3. The shutter mechanism has not been shown in detail for the reason that it is not a part of this invention.

The operating mechanism which is shown best in Fig. 3 comprises, generally, a motor element l4 and a, gear reduction and clutch element l5. The

gear reduction portion of element comprises, a shaft I6 mounted in a suitable casing or housing H on bearings l8 and 19, as shown. The shaft l6 extends through the ends of the housing and carries at one end a drive gear 2| and at the opposite end an operating handle 22. As shown in Fig. 2, the drive gear 2! meshes with the drive gear ll of the shutter mechanism.

In this instance, the motor element I4 is of the commutator type. As shown, this motor element comprises a field structure 24 and an armature 25 having a commutator 25 mounted within a suitable motor casing 21. In this instance, the motor casing 21 is secured directly to one side of the housing ll by means of a plurality of tie bolts 28. One end of the armature 25 is rotatably supported in a bearing 3| mounted in the closed end of the motor casing, and the other end is supported by a bearing 32 mounted in a suitable recess on the side of the housing H.

The motor element 14 is connected in driving relation with the shaft I6 by means of a suitable gearand clutch arrangement, indicated generally at 33. This comprises a main bevel gear 34 rotatably mounted upon the shaft l6 and a cooperating pinion 35 secured to the end of the motor shaft. This constitutes the gear reduction and permits the use of a relatively small high speed motor.

This arrangement further comprises a clutch element 38 which, in this instance, is in the form of a spring disk or cup rigidly secured to the shaft It. This disk 36 may be secured to the shaft in any suitable manner, but in this instance is mounted directly upon the hub portion 31 of an arm or snubber 38.

It will be understood that the disk 35 and the bevel gear 34 cooperate to provide a slip clutch connection between the motor and the shaft It. The rounded face or rim portion M of the member 36 frictionally engages the flat back face of the gear 34, as shown.

The clutch tension may be adjusted in any suitable manner, but in this instance it is effected by means of the nut 42 disposed upon the end of the shaft l6 and also utilized for the purpose of retaining the drive gear 2! in position. It will be apparent that by adjusting this nut 42, the shaft 16 may be moved endwise in such manner as to vary the clutch tension or pressure.

In this instance, the arm or snubber 3-8 is utilized to limit the travel or degree of rotation of the shaft 16, as will be described more in detail hereinafter.

It is to be understood that the shaft I6 is driven in one direction by the motor 14, and when the mechanism is being used to actuate a signalling shutter on a Searchlight, this direction of rotation of the shaft l6 effects the opening of the shutter blades. Since the blades simply move between open and closed positions, it is necessary to return the operating mechanism to an original starting position when the shutter blades close. In this instance, the shaft I6 is biased in the opposite or closing direction of rotation by means of a coil spring 43 mounted within a cup-shaped portion 44 of the handle 22. As shown, one end of this spring engages a notch 48 in the circular flange portion 49 of the front cover 46 of the casing IT, and the other end 41 is attached within the cupshaped portion 44. This spring 43 is of such strength as to return the shutter or other device to its closed position when the motor is deenergized. When the motor is energized, it drives the shaft I5 and its load against the opposing force of the spring 43. If desired, a number of notches 48 may be provided in spaced relation in the flange portion 49 for permitting the end 45 of the spring to be set in different positions to adjust its tension in a well known manner.

While the shutter or other device with which this operating mechanism may be used has a definite range of travel and is usually provided with stops at either end of its range of travel, the arm or snubber 38 secured to the shaft 15 together with a pair of stops, indicated generally at 51 and 52 in Fig. 2, are utilized to limit the rotational movement of the shaft I6. In this instance, two stops are used with a common snubber or arm 38 in order to limit the movement of the shaft in either direction.

Each of the stops 5| and 52 is disposed in the path of travel of the snubber 38 and is so constructed that it may be adjusted from the outside of the casing [1.

.As shown in Fig. 2, each of the stops comprises an anvil member 53 mounted for longitudinal movement in a cup or recess 54 and biased to an outward position, as shown by means of a coil spring 55 backed up by an adjustable threaded plug 56 which is maintained in any desired position by the lock nut 51. As will be understood, this arrangement provides for adjusting the tension of the biasing spring 55 and, consequently, the force with which the anvil 53 is urged outwardly toward the snubber 38.

In the normal operation of the mechanism, as the snubber 38 reaches the end of its travel, it strikes the anvil 43 and drives it against the spring 55. The spring 55 is so adjusted that :the torque applied to the shaft l6 by the motor and the load of the spring 55 are substantially equal when the shutter or other device reaches its open position. The tension on the clutch 36 isso adjusted by means of the lock nut 42 that a slight slippage occurs when the snubber 38 strikes the anvil 53.

It will be understood that the snubber and anvil arrangement functions ;to soften the end of the travel position blow initiated by either the motor M or the return spring 43. In other words, when the mechanism is functioning to drive the shutter of a Searchlight to the open position, the snubber 38 strikes one of the resiliently mounted anvils 53 just prior to the time the shutter reaches its full open position, and its own stop prevents its further movement. The striking of the snubber 38 against its cooperating" anvil softens the stopping blow and initiates the necessary slippage of the clutch 38. The other anvil functions to cushion the blow in the opposite direction when the spring 43 returns the mechanism to its starting position.

In order to provide for positively locking the mechanism and the shutter or other device that itdrives in definite positions, a locking pin 6! is mounted on the cup-shaped portion 45 of the handle in such manner that it may be moved endwise to a disengaged position, as shown, or to a locking position where it engages one of a plurality of recesses 62 in the face of the cover 45. Only one of the recesses 32 is shown, but it will be understood that the other recess, where only two are used, is displaced therefrom at any desired position where it may be engaged by the end of pin 5| to hold the mechanism in another position.

As shown in Fig. 4, the locking pin BI is retained in either of its operating positions by means of a releasable catch arrangement comprising, a ball 63 biased to engage either one of the circular notches 64 and 65 on the pin by a spring 66 adjustably retained in position by means of a screw 61.

In view of the foregoing description of a preferred embodiment of my invention, it will now be apparent that it makes possible the use of a motor of the commutator type for operating signalling shutters and the like. The use of the gear and clutch arrangement between the drive motor and the shutter not only makes it pos sible to use a motor of the commutator type, but also a smaller motor than that which could be used with a direct drive. The use of a slip clutch arrangement permits the motor to operate in a normal manner so that it is not required to start from the same identical position each time, which would result in burning of its commutator segments. The slippage of the clutch causes the motor to stop in different positions each time the shutter reaches the end of its opening travel.

This arrangement also provides for effecting an improved operation of the signalling shutter in that very fast acceleration of the shutter is obtained. Faster opening and closing movement of the shutter are effected because of the low inertia of the operating mechanism and its various parts. The use of a small motor as compared to a large motor in other mechanisms reduces the current requirements and provides a constant torque from start to full open position of the shutter. All of this results in a mechanism having a relatively long life because the inertia hammering has been reduced to a minimum.

While I have disclosed a particular embodiment of my invention, it will be understood that changes and modifications may be made therein without departing from the principles of the invention.

I claim as my invention:

1. An operating mechanism for use with a device having fixed limits of movement or travel comprising, a shaft, a motor, means including a slip clutch connecting the motor in driving relation with the shaft, resilient stop means for limiting the movement of the shaft when driven by the motor, spring means normally biasing the shaft to a starting position and operable to return the shaft to said position when the motor is deenergized, a manual operating lever attached to the shaft for actuating it independently of the motor, and means carried by said lever for looking the shaft against rotation in a plurality of positions.

2. An operating mechanism for use with a device having fixed limits of movement or travel comprising, a housing, a shaft journalled in the housing and extending therefrom at both ends, a drive gear mounted on one end of the shaft, an operating lever mounted on the opposite end of the shaft, spring means normally biasing the shaft to a predetermined starting position, a bevel gear element rotatably mounted on the shaft within the housing, a snubber arm attached to the shaft adjacent the bevel gear element, a

resilient member mounted on said arm cooperative with the bevel gear element to provide a slip clutch, means for adjusting the position of the shaft longitudinally to vary the tension of the slip clutch, a stop member mounted on the housing in the path of travel of said arm, spring means biasing the stop member toward said arm, and means for adjusting the tension of said spring means.

3. An operating device for use With a device having fixed limits of travel comprising, a housing, a main shaft rotatably mounted within the housing, a motor mounted on the housing with one end of its armature shaft extending therein, gear means interposed between th armature shaft and main shaft including a gear element rotatably mounted on the main shaft, and a resilient member attached to the main shaft adjacent the gear element and frictionally engaging the back face thereof, said gear element and resilient member constituting a slip clutch, and spring means interposed between the housing and main shaft normally biasing said shaft to a predetermined starting position.

4. An operating mechanism for use with a device having fixed limits of movement comprising, a housing, a shaft rotatably mounted in the housing and extending therefrom at one end, a drive gear mounted on the shaft extension, a gear member rotatably mounted on the shaft within the housing, a clutch member attached to the shaft in cooperative relation with said gear member, a motor of the commutator type mounted on said housing, said motor having a drive pinion engaging the gear member, a spring member normally biasing the shaft to a predetermined starting position, an arm carried by said shaft, and a resiliently mounted stop member mounted on the housing in the path of said arm to stop the shaft in a predetermined position while permitting the clutch to slip so that the motor may stop in a different position each time it is operated to drive the shaft to its stopping position.

WILLIS A. PENNOW.

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

UNITED STATES PATENTS Number Name Date 675,388 Keating June 4, 1901 801,012 Howard Oct. 3, 1905 1,266,280 Kocourek May 14, 1918 1,611,963 Valentine Dec. 29, 1926 1,634,942 Hillborn July 5, 1927 1,654,943 Nott Jan. 3, 1928 2,069,440 Hathorn Feb. 2, 1937 2,286,419 Krenzke June 16, 1942 2,295,419 Miskelly Sept. 8, 1942 2,381,390 Vanke Aug. 7, 1945 FOREIGN PATENTS Number Country Date 145,833 Great Britain June 28, 1920

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