US2517079A

US2517079A - Control mechanism

Info

Publication number: US2517079A
Application number: US671356A
Authority: US
Inventors: Edwin H Birdsall
Original assignee: Individual
Current assignee: Individual
Priority date: 1946-05-21
Filing date: 1946-05-21
Publication date: 1950-08-01
Anticipated expiration: 1967-08-01

Description

g- 1, 1950 E. H. BIRDSALL 2,517,079

CONTROL MECHANISM Filed May 21, 1946 2 Sheets-Sheet 1 s4 l l l I 1 I I muse ADJUST 15mm, LOWER IFOLLOWER: FULGRUM cm iFoLLowER INVENTOR.

EDWIN H. BIRDSALL A Horney Aug. 1,. 1950- E. H. BIRDSALL' 2,517,079

CONTROL MECHANISM Filed May 21, 1946 2 Sheets-Sheet 2 INVENTOR EDWIN H. BIRDSALL ATTORNEY Patented Aug. 1, 1950 CONTROL MECHANISM Edwin H. Birdsall, San Diego, Calif., assignor to United States of America as represented by the Secretary of the Navy Application May 21, 1946, Serial No. 671,356

6 Claims.

This invention relates, in general, to a control mechanism and, in particular, to a cam shaft shifting control device contained within a student training apparatus or the lik requiring that any one of a plurality of different control motions be imposed thereon in order to present a variety of problems such as may be encountered in combat.

It is common practice in the training of student operators, whether they are to be future radio or underwater sound operators or the like, for an instructor through the manipulation of master controls to set up a variety of simulated signals which as nearly as possible reproduce the signals to be received under actual operating conditions. In sonar training devices, for example, these simulated signals are fed to any desired number of sonar receivers operated by the students who in time learn to distinguish between the various received echoes, reverberation noises and the like. Quite frequently the simulated signals are generated through cam action operating associated equipment, and in the course of the instruction it is often necessary to quickly change from one set of signals to another by the interchange of cams. It is further desirable that any of the cams be selected at will, without the necessity of following a fixed sequence once the equipment is set into operation. The present invention relates to a device for rapidl changing the above-described control cams.

It is one object of this invention to provide a motion initiating and control device which is adapted to be rapidly and easily adjusted to provide the desired movement of the apparatus with which it may be associated.

Another object of this invention is to provide a train of cams so associated with one another and with the followers with which they engage as to eliminate the necessity of disassembling, interchanging, and reassembling the cams, as is the usual procedure in most cam control apparatus presently employed.

Still another object of this invention is to provide a compact, simple, rugged and relatively inexpensive electricall operated control apparatus. j

These, and other objects, as well as the various other novel features and advantages of this invention will become apparent from a reading of the specification and accompanying drawings of which:

Figure 1 is an isometric view of the control device, showing the electrical elements associated therewith, and

Figure 2 is an enlarged View of a portion of the cylindrical cam.

Figure 3 is an enlarged sectional view of the clutch arrangement for operating the cam followers.

With reference to the drawings, this invention comprises a series of cams, groups I I and I2, consisting of cams Ila, lib, and Ho and IZa, H11, and I 20 respectively, positioned on shaft 13, adapted to engage followers 14 and I5 respectively, cam shifting unit I6 and cam shifting unit electrical control system I I. Shaft I3 and cam groups I I and i2 rotate by means not shown and not a part of this invention for the purpose of operating switches or other signalling apparatus, likewise not illustrated, by the action of the cam followers 14 and 15.

The cam shifting unit I6 embodies a rotatable drum I8 secured to shaft It, having

circular flanges

21 and 22, the flange 22 being undercut at 23 for a portion of its circumference. Secured to flange 2i is a pin 24 adapted to be received within a recess 25 of a cam follower rocker arm 29 attached to shaft 2? upon which the followers I4 and [5 are positioned. The hub or central portion of drum I8 is undercut to define a path 28 within which a pin 29 of cam shifting lever 3| is received. The path 28 is adapted to provide operating zones for four cam motions, namely, zones within which the followers are raised, the cam shifting lever set, the cams shifted and the followers lowered respectively. A gear 32 secured to the shaft I9 engages with worm gear 33 rotated by electrical motor 35 for driving the drum I8. Cam followers l4 and 15 are rotatably mounted upon shaft 21 so that when the rocker arm 26 is actuated, the followers are pulled away from the cams by Virtue of the clutch arrangement 30. As soon as the shaft is returned to its operable position, followers I4 and I5 also are returned through the action of suitable springs mounted in the base or hub portions 35 and 36 thereof. A typical construction for one of the clutch arrangements is clearly shown in Fig. 3 wherein the base 36 has a hollow sleeve-like portion l2 through which the shaft 27 extends. Within the sleeve portion I2 is a spring l3 coiled concentrically about shaft 2'! and having one and M inserted through a hole in shaft 21 and the other end I5 inserted in a slot in sleeve portion i2, whereby, due to the action of the spring, the cam follower I5 is urged against one of the cams 12a, I25, or I20. The spring 73 urges follower it in a counterclockwise direction as viewed from Fig. 3. Closing the end of sleeve portion 12, but in freely sliding contact therewith is a collar it which may be attached to shaft 21 by means of set screw?! whereby the cam follower I5 is prevented from moving axially along shaft 21. The member 39, forming the other portion of the clutch arrangement is rigidly attached to shaft 27 by means of a set screw 18, or the like.

The electrical control system I! is made up of a selector switch 3], having a suitable electrical connection to a source of power, to stationary contacts 31a, 31b, 31c, and to three pairs of

switching contacts

38, 39 and 4|, which contacting elements are so associated with a relay 43 and additional switching contacts 44 as to insure proper electrical connection between the power source and the direct current motor 45 and alternating current motor 3 3. A worm gear t5 keyed to the shaft of direct current motor 45 engages with a gear 41 positioned on shaft 48. is mounted in suitable bearings 49 and provided with a plurality of cams 5!, 52 and is for opening the particularly desired electrical contacting elements of the

group

38, 39 and ll. The lower end of shaft $8 is firmly secured to an adjustable fulcrum 54. The fulcrum 54' is provided with anopening 55 within which is rotatably received a pin 55a secured to cam shifting lever 35. Thus, the lever 3i is not only supported at the end of shaft 18 but is permitted to pivot about the pin 55a for effecting the cam shifting action.

Selector switch 317 comprises a movable con tacting arm 56 which may be moved into any one of three positions (as shown) for closing an electrical circuit between one of the power lines and One of the contacting

elements

38, 39 or M for purposes to be hereinafter disclosed.

The relay 43 is provided with an electromagnet BI, and two

stationary contact elements

62 and 63 with a movable contact as mounted therebetween which is adapted to be drawn from its initial position of contact with element E52 into con" tact with element I35 when the electromagnet is energized. The support for element fi l is sufficiently resilient as to cause the element to return to'its initial position upon deenergization of the electromagnet. In addition, two switches 65 and 6,6 are provided for closing or opening electrical circuit between D. C. motor 45 and A. C. motor 34 respectively.

The operation of this control device is carried out essentially in the following manner:

From the control position as illustrated in the drawing, let it be supposed that the operator desires to impose a new problem on the apparatus associated with and controlled by the followers I4 and I5 and that the motion desired will be that incident to engagement of followers Hi and I5 with cams Ila and Ho respectively.

The movable arm 58 of selector switch 31 is rotated so that it makes contact with element 31a thus energizing electromagnet 5|. The magnet draws element 64 into contact with element t3 and, since switch 65 is closed by virtue of element 65a having dropped down into undercut portion 23 of flange 22 when the drum I8 is in the position in which the cam followers Id and I5 are to be raised, the armature of motor 25 is excited and current furnished to the field winding thereof so that the motor begins to rotate driving the shaft as, thus moving the cam 5! into engagement with the movable contact of switching elements 38. At the same time electromagnet 6| closes contact M to energize motor 34. It will be apparent that as soon as they cam 5i has travelled sufiiciently far, the circuit will be broken at the switch 38, which in turn will deenergize the electromagnet 61 to cause switch The shaft 38 V element 64 to return to position of contact with element 62. The motor 45 is immediately brought to a stop and as the armature thereof is short circuited by reason of switch 65 being closed, coasting of the motor is prevented.

However, even though motor 45 is brought to a stop, upon completing the function of moving fulcrum 54 to the desired number one position, during the time pin 29 of cam shifting arm 3| is Within the wide or fulcrum shifting position of cam path 23, the motor 34 continues to rotate inasmuch as the switch 65 is still closed. As the drum I3 rotates further, the pin 29 will strike the side portions of the circular cam path 28 and cause the arm SI to pivot about pin 55a thus shifting the cams to their new positions by virtue of the axial movement imparted thereto by the knob 6! secured to the end of arm 3! and positioned between flanges 20a of drum 20.

Pin 24, of drum I8, rises to carry the rocker arm 28 to its high position so that the followers I4 and I5 are lowered and brought into engagement with the cams Ila and 12a and finally the rocker arm will be engaged with the movable contact of switch as, opening the switch 66 and causing motor M to be brought to a stop.

As the cams have now been shifted to their new- 1y selected positions, it is merely necessary to rotate the shaft 53 in order to impart the desired motions defined by the cams to the cam followers l5 and 5 for imposing a new problem on the apparatus associated with the followers.

It will be understood that the above description and accompanying drawings comprehend only the general and preferred embodiment of the invention and that various changes in construction and proportion as well as arrangement of the parts thereof may be made within the scope of the appended claims without sacrificing any of the advantages of the invention.

I claim:

1. In a control apparatus, the combination comprising a plurality of cams, a plurality of followers associated with said cams, means for moving said followers into and out of engagement with said cams, means for shifting said cams axially with respect to their axes of rotation, and cam shifting preselection means for determining in advance the position into which said cams are to be shifted comprising a selector switch, a motor, a plurality of switches interposed between said selector switch and said motor and means operable by said motor for interrupting the circuit between the one switch of said plurality closed by the operation of said selector switch and said motor.

2. In a control apparatus, the combination comprising a plurality of earns, a plurality of followers associated with said earns, a shaft supporting said followers, a rocker arm secured to said shaft, means for rocking said arm in a clockwise or counterclockwise direction, clutching means adapted to engage with said followers to cause rotation thereof together with said shaft when said shaft is rotated in one direction, means for shifting said cams axially with respect to their axes of rotation, and cam shifting preSelection means for determining in advance the position into which said cams are to be shifted comprising a selector switch, a motor, a plurality of switches interposed between said selector switch and said motor and means operable .by said motor for interrupting the circuit between said selector switch and said motor by operating one of said plurality of switches.

3. In a control apparatus the combination comprising a plurality of cams rotatable about a common axis, a plurality of followers associated therewith adapted to be moved into and out of engagement with said cams, driving means associated with and adapted to provide inward and outward movement of said followers, control means associated with said driving means, means adapted to shift said cams axially with respect to said followers to cause a selected group of cams to come into registration with said followers, and control means associated with said last-mentioned means for insuring movement of said cams to their selected positions.

4. Control apparatus for shifting a plurality of cams axially with respect to their axes of rotation and into and out of engagement with a plurality of cam followers comprising a selector switch for determining in advance the position into which said cams are to be shifted, a first motor, a plurality of limit switches, means driven by said first motor for operating said limit switches, a second motor, drum means driven by said second motor, said drum means acting to move the cam followers out of engagement with said cams and to shift said cams and to move said cam followers into re-engagement with said cams.

5. Control apparatus for shifting a plurality of cams axially with respect to their axes of rotation and into and out of engagement with a plurality of cam followers comprising a. selector switch for predetermining the position into which said cams are to be shifted, a first motor, a plurality of limit switches in the circuit between said motor and said selector switch, means driven by said first motor for operating said limit switches, a cam shifting lever, said first motor driven means acting to alter the fulcrum of said cam shifting lever, a second motor, drum means driven by said second motor, said drum means having a recess in the face thereof for receiving one end of the above-mentioned cam shifting lever, said recess acting to apply force to said cam shifting lever to thereby shift said cams when the drum means revolves.

6. The apparatus of claim 5 in which said drum means has a pin in one face thereof, and a cam follower lever adapted to be moved by said pin, said pin acting to move the aforementioned plurality of cam followers out of engagement with said cams while said cams are being shifted and to re-engage said cam followers and cams after the shift.

EDWIN H. BIRDSALL REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,094,777 Ellinger Oct. 5, 1937 2,359,059 Somes Sept. 26, 1944