US3323814A - Electromechanical actuator package - Google Patents

Description

June 6, 1967 J. J. PHILLQPS ELECTROMECHANICAL ACTUATOR PACKAGE Original Filed Nov. 2, 1962 2 Sheets-Sheet 1 "I'IIEVII'III I mvsmoa troy/v If. Pia/1.1.105

June 1967 .1. J. PHILLiPS r ELECTROMECHANICAL ACTUATOR PACKAGE 2 Sheets-Sheet 2 Original Filed Nov. 2, 1962 INVENTOR. Jay 1']; Paula/p5 United States Patent 3,323,814 LECTROMECHANICAL ACTUATOR PACKAGE John J. Phillips, Rolling Hills, Califi, assignor to Gray & Huleguard, Inc., Santa Monica, Calif., a corporation of California Continuation of application Ser. No. 235,611, Nov. 2, 1962. This application Dec. 24, 1964, Ser. No. 421,165 Claims. (Cl. 287-20) This is a continuation of my copending application Electromechanical Actuator Means, S.N. 235,611, filed Nov. 2, 1962, now abandoned.

This invention relates generally to electromechanical actuators, and in particular concerns a novel actuator package of the electromechanical type, characterized in that elements of the package undergo rapid and relative exansion in response to the application to the package of a predetermined electrical signal.

It is a major object of the invention to provide improvements in an electromechanical actuator package that includes a pair of relatively movable bodies extending in collapsed relation and spring means exerting load tending relatively to expand the bodies from collapsed relation. One important improvement contemplated by the invention concerns the release of latch mechanism having releasably interengaged shoulders through which at least some reaction loading is transmitted for controlling relative expansion of the bodies. As will be brought out, the electrically energizable release acting on the latch mechanism to hold the shoulders against disengagement includes a current fusible part a predetermined first portion of which has relatively greater heat exchange relation with the exterior thereof, and a predetermined second portion of which has relatively lesser heat exchange relation with the exterior. The construction is such that suflicient current passed through the fusible part will effect release of the latch mechanism and consequent expansion of the bodies by preferred fusion of said part at the predetermined second portion thereof, the current also being subject to increase to the point where the first portion of the fusible part will fuse or expand sufiiciently to effect release of the latch should the first portion fail for any reason. Accordingly, the reliability of the release is increased substantially over the reliability factors of releases having parts the fusion locations of which are not predetermined.

More particularly, the fusible part may comprise a loop of Wire, or its equivalent, extending about generally cantilevered retaining fingers which are circularly spaced and held against fiexure by the loop to prevent disengagement of the latch shoulders. Typically, the release includes a heat insulative body in which said second portion of the loop is embedded, whereby heat generated by current flow through the loop will tend to be retained within the insulative body for effectiing rapid temperature increase, whereas heat generated in the loop contacting the metal cantilever fingers will escape to such fingers producing a less rapid temperature increase.

Another object of the invention concerns improvements in the construction of the previously mentioned cantilever fingers, these having reduced thickness fiexures for urging the end portions of the fingers outwardly after fusion of the loop-like fusible part, thereby releasing the retained latch member to permit relative expansion of the bodies. The reduction in thickness of the flexures does not adversely affect tthe ability of the fingers to retain the bodies against expansion, but does permit the use of a smaller gage wire 100p fusible part, which in turn requires less current application or flow therethrough to effect the fusion release.

A still further important object of the invention concerns the provision of auxiliary means releasably attachable to one of the relatively movable bodies for decou- 3,323,814 Patented June 6, 1967 pling therefrom in response to said expansion. As will be brought out, such auxiliary means typically comprises a third body, with auxiliary latch means coupling the third body to one of the first and second bodies for decoupling the third body after predetermined relative expansion of the first and second bodies. Accordingly, the application of electrical current to the fusible part previously mentioned will effect expansion of the first and second bodies, and decoupling of the third body, all in a very simple and effective manner, with'rninimum risk of malfunction. Additional spring means may be provided for exerting force in a direction such as to urge the third body away from the first or second bodies after said decoupling.

These and other objects and advantages of the invention, as well as the details of an illustrative embodiment, will be more fully understood from the following description of the drawings, in which:

FIG. 1 is a perspective showing of one of the bodies with the cantilever fingers shown held against flexure by the current fusible part;

FIG. 2 is a sectional elevation taken through the actuator package prior to release;

FIG. 3 is a section line 33 of FIG. 2;

FIG. 4 is a view like FIG. 2 showing the package after release, with the auxiliary body decoupled;

FIG. 5 is a section taken on line 5-5 of FIG. 2;

FIG. 6 is a sectional elevation taken through a modified actuator package prior to release; and

FIG. 7 is a View of the package shown in FIG. 6 after release and ejection of the auxiliary body.

Referring first to FIGS. 1 through 5, the electro-mechanical actuator package illustrated comprises an assembly 10 including first and second bodies 11 and 12 extending in collapsed relation in FIGS. 2 and 3. The first body, which encloses the second body, is shown in one of its possible forms to include a cylinder 13 having one end thereof closed at 14 and attached to a suitable support 15 as by means of the threaded connection 16. The open end 17 of the cylinder is interiorly threaded to receive a plug 18, which is externally threaded for engagement at the thread location 19. The second body 12 is shown in one of its possible forms to include a shaft 20 received within the plug bore 21, an extension 22 and a suitable stop member 23 spaced from the interior end wall 24 of the first body end 14.

The package also includes spring means exerting loading tending relatively to expand the bodies from collapsed relation, and latch mechanism having releasably interengaged shoulders through which at least some reaction loading is transmitted for controlling relative expansion of the bodies. As illustrated in the drawings, one form of spring is shown at 25 as axially compressed between the plug shoulder 26 and the face 27 of a latch plate 28 carried on the second body extension 22. Since the thickness of the plate is less than the spacing between the shoulders 29 and 30 respectively on the shaft 20 and stop member 23, it is clear that the plate and the secondbody may have limited relative axial movement, the purpose of which will be brought out later.

The previously mentioned releasably interengaged shoulders may typically be provided on the plate 28 as shown at 31, and on thickened portions of retaining members such as the series of circularly spaced longitudinally extending cantilever fingers 32, the shoulders thereon being indicated at 33. The shoulders 31 and 33, when interengaged, typically lie in a frnsto conical plane tapering rightwardly as shown in FIG. 2, such plane being co-axial with respect to the axis 34 of the assembly. Accordingly, the plate 28 is retained by the retaining fingers 32, and is releasable for rightward expansion after sudden spreading of the fingers 32 as brought about by the outward camming action of the plate 28 acting on the fingers through the shoulders 31 and 33. The spring 25 reacts between the plug shoulder 26 and the plate 28 and thereby forces the frusto-conical shoulders 31 and 33 against each other. Because of the angularity of these shoulders a Wedging force is produced that tends to spread the cantilever fingers 32 radially outwardly. If the fingers 32 are not restrained and free to move they will move out enough to allow the plate 28 to pass therethrough. The amount of the radially outwardly directed force on the fingers is, of course, a function of both the magnitude of the biasing force from the spring 25 and the conical angle of the shoulders 31 and 33.

In addition to the foregoing spreading action of the spring 25 cantilever fingers have reduced'thickness flexural extent 35 for urging the end portions of the fingers 32 radially outwardly to' aid release of the latch mechanism. The bases of fingers 32 are integral with flange 36 and suitably attached to the plug 18 by fasteners 37. As is clear from the drawings, the flange 36 may be assembled to the plug prior to screwing of the plug into the first body cylinder 13.

In accordance with the invention, an electrically energizable release is provided to hold the shoulders 31 and 33 against disengagement. One form of such release is shown to include a current fusible part, as for example a generally hoop-like member or wire 38 extending about the thickened free end portions of the cantilever fingers 32 to hold them against outward flexure prior to fusion of the member 38. The wire member 38 encircles the outer ends of the fingers 32 and tightly wound therearound. As a consequence the wire 38 is effective to re tain the ends of the fingers 32 in a radially inner position with the shoulders 31 and 33 in intimate engagement. The spreading forces produced on the fingers 32 by the spring 25 and shoulders 31 and 32 will thereby produce a tension force in the wire member 38. The magnitude of this tension in the wire 38 is, of course, a function of the resiliency of the fingers 32, the force of spring 25 and the angularity of the shoulders 31 and 33. At ambient temperatures for the assembly 10, the tensile strength of the wire 38 is, of course, adequate to retain the tension forces normally created therein. This is effective to retain the fingers 32 in their radially inner positions. The latter has a predetermined first portion 42 typically in engagement with the fingers 32 at the groove location 39, withconsequent provision of heat transfer between the said first arcuate portion of the metal loop 38 and the metal fingers. Such heat transfer is characterized in accordance with the invention as being relatively greater than the heat losing capacity respecting a predetermined second portion 41 of the member 38. Typically said second portion 41 is much shorter than said first portion and is embedded within a heat insulative body of any suitable material such as the resinous body shown at 40. Accordingly, when suflicient current is passed through the part 38 fusion will' occur at the predetermined second portion or portions 41 rather than at the predetermined first portion 42, and less current application, or a shorter time interval of such application will be required than if the entirety of the member 38 contacted the metallic fingers 32. It is understood that fusion occurs when suflicient development of heat due to the current resistance of the member causes the temperature to rise to the fusion level i.e. the level at which the heat softened, hoop terminal member 38 fails and suddenly expands. It is a well known characteristic of metals that they have their greatest tensile strength at normal temperatures. This strength remains relatively constant over a broad range of temperatures. However, if the temperature is raised to some elevated level, for example in the region of red hot, the tensile strength of the metal gradually begins to decrease. However, beyond this point, forexample red hot, even relatively small increases in temperature cause very large decreases in the tensile, i.e. the strength decreases at a very rapid rate. Of course when the temperature actually reaches the melting point the tensile strength is zero. As a consequence as the temperature of the wire 38 increases toward the melting point, at some point in this temperature rise the tension in the wrie 38 will exceed the tensile strength of the wire 38 and the wire 38 will rupture or mechanically fail and break. This rupture of the wire occurs sometime before the temperature actually reaches the melting point. Terminals for passing current to the member 38 are shown at 43 and 44, a suitable terminal block being illustrated at 45 as mounted by the plug 18. A source of current is shown in FIG. 1 at 46.

In operation, failure of the member 38 releases the cantilever fingers 32 for outward flexure, thereby releasing the plate 28 to be urged rightwardly by the compressed spring 25. As the plate moves rightwardly it achieves sufiicient velocity and momentum to forcibly strike the shoulder 30 of the stop member 23, suddenly and sharply accelerating the latter and the shaft 20 rightwardly to the point where the stop member strikes the interior end face 24, as illustrated in FIG. 4. Such delayed pick-up and expansion of the second body 12 relativeto the first body 11 enhances rapid and timewise accurate decoupling of auxiliary means, generally indicated at 47, from the first body 11.

As previously mentioned, the invention contemplates the decoupling from one of the bodies of auxiliary means in response to relative expansion of the first and second bodies. One form of such auxiliary means 47 is shown in the drawings to comprise a third body 50 coupled to the plug 18 of the first body 11, with bosses 51 and 52 received in the plug counterbores 53 and 54. The releasable coupling of the third body to the plug is such as to provide for sudden decoupling after predetermined relative expansion of the first and second bodies. Typically, second or auxiliary latch means is provided for this purpose, and includes a retained member in the form of an interior flange 55 on the hollow boss 51, together with retaining members typically comprising a series of circularly spaced, generally longitudinally extending cantilever fingers 56 held against inward flexure by the second body shaft 20.

More particularly, the cantilever fingers 56 include dogs 57 received within the hollow boss 51 and blocking the third body flange 55 from leftward displacement as shown in FIG. 2. As long as the end of the keeper shaft 20 is disposed within the dogs 57 they will be restrained against radially inward movement. As a consequence they will be maintained against the flange 55 and the auxiliary member 47 will be locked in position. Even though there may be very large forces pulling on the auixiliary means 47 none of this force will be transferred to the keeper shaft 20. In fact the pin 12 may be axially moved (within limits) without in anyway releasing the dogs 57. Thus the radially expanding forces on the fingers 32 and the tension in the wire 38 are independent of the load on the auxiliary means 47. Only after the cantilever fingers 56 flex inwardly, as permitted by sudden rightward travel of the second body shaft 20, are the dogs 57 moved inwardly sufliciently to allow leftward displacement of the third body 50, as shown in FIG. 4. Such sudden rightward displacement of the second body shaft 20 is assured by virtue of the previously mentioned initial momentum developed by the plate 28 as it travels rightwardly prior to picking up the second body stop member 23 to carry the shaft 20 rightwardly. The resultant sharp acceleration of the shaft 20 in a rightward direction is sufiicient to overcome any systems friction, as for example may be developed by engagement of the dogs 57 with the shaft 20, and engagement of the enlarged bearing flange 58 on the shaft with the inner surfaces of the cantilever fingers 56. The latter are initially sprung inwardly, as shown in FIG. 4, so as to require spreading by the shaft 20 and the flange 58 into the retaining condition shown in FIGS. 2 and 3.

Referring now to FIGS. 6 and 7, the elements are substantially the same as previously described in connection with FIGS. 1 through 5, as respects the functioning of the actuator package. Thus, the package includes first and second bodies 60 and 61 which are relatively axially movable and extend in co-axial relation in FIG. 6. The first body 60 includes a cylinder 62 having a closed end 63, and a plug 64 closing the opposite end of the cylinder. A new element in the form of a barrel 65 is added, the latter being suitably attached to the plug 64 as by threading 66. Furthermore, the barrel is attached to a mounting plate 67 as by means of a connector 68 retained between the plug 64 and a barrel flange 69, washers 70 being provided as shown. An inner bar-rel 71 within the outer barrel 65 receives the shaft 72 of the second body 61, for axial relative movement therein.

Means exerting loading tending relatively to expand to. bodies 60 and 61 is shown at 73 in the form of a series of circularly spaced springs 74 received on fixed shafts 75. The latter extend between stacked plates 76 and 77 adjacent the closed end 63 and the boss 78 of the plug 74. The rightward terminals of the springs 74 urged a second body plate 79 rightwardly, that plate in FIG. 6 being peripherably held against rightward displacement by the circularly spaced cantilever fingers 80. The latter and the plate have releasably interengaged shoulders 81 and 82 through which reaction loading is transmitted for controlling relative expansion of the bodies. Shoulders 81 are on thickened portions 83 of the fingers, the latter also having reduced thickness flexures 84 extending leftwardly toward the plate 76 with which the fingers are integral.

The electrically energizable release acting to hold the shoulders against disengagement typically includes the hoop-like wire 85, the first arcuate portion of which is in contact with the finger portions 83 forming a peripheral groove 86 generally rightwardly of the plate 79, the wire typically comprising copper or other suitably electrical conductive material. The second portion of the fusible part or wire, which has relatively lesser rate of heat loss capacity to the exterior, is typically embedded in the insulative block 87 carried by one or two of the cantilever fingers as shown. Accordingly, when suflicient current is passed through the fusible part, as by means of the leads 88 having electrical connection with the input terminal 89, the wire or part undergoes fusion expansion i.e. mechanical failure within the block 87 to release the cantilever fingers for sudden spreading as the plate 79 is urged rightwardly by the spring 73. The shoulders 81 and 82 are sufiiciently angled to provide the camming action required for such spreading and to maintain the tension in the keeper wire 85.

As the shaft 72 of the second body moves rightwardly Within the interior barrel 71, it effects release of the auxiliary means generally indicated at 90 in FIG. 7. Such auxiliary means typically includes a third body 90 releasably coupled to the second body, as for example to the second body barrel 71. As shown in the drawings, the coupling typically includes a second set of cantilever fingers 91 on the inner barrel 71 and provided with dogs 92 shown in FIG. 6 as blocking rightward relative displacement of the third body flange 93. The cantilever fingers 91 are held spread apart in the condition shown in FIG. 6 by an enlarged portion 94 of the shaft 72. When such portion is displaced rightwardly relative to the dogs 92 and as shown in FIG. 7, the cantilever fingers 91 are deflected inwardly, either as a result of initial inward springing or inward camming of the fingers produced by the cam shoulder interengagement at 100.

The invention contemplates the provision of additional spring means exerting force in a direction such as to urge the third body away from the second body to which it is coupled. One form of such spring means is shown at 95 in FIGS. 6 and 7 to comprise a compression spring retained between plug body 78 and a plunger head 96 located between inner and outer barrels 71 and 65. The head 96 is carried on the cylindrical plunger 97 which projects from the outer barrel at 98 in FIG. 1 and termi- 6 nates proximate the third body and in particular the third body flange 93. Accordingly, when the third body is released, the spring forceably urges the plunger 97 rightwardly to suddenly displace the third body rightwardly in the direction of the arrows 99 in FIG. 7.

I claim:

1. An electromechanical quick disconnect package for releasably restraining a load, said package comprising the combination of,

a first member adapted to be connected to said load,

a second member effective to releasably mate with the first member, said second member being adapted to be connected to a support for carrying the load,

a shoulder on one of said members,

a detent on the other of said members effective to engage said shoulder and secure said members together,

a keeper moveable between first and second positions, said keeper when in the first position being effective to maintain said detent in engagement with said shoulder, said keeper when in the second position being effective to release the detent from the shoulder,

spring means coupled to said keeper to bias it into the second position, plurality of resilient fingers coupled to the spring means and said keeper for maintaining the keeper in the first position, said spring means being effective to produce a force on said fingers to deflect them whereby the keeper is released into the second position,

an electrically conductive wire secured to said fingers and effective to maintain them coupled to the spring means and said keeper, said wire having a tension which is produced by said spring means, and

means for circulating a current through said wire until its tensile strength is less than said tension.

2. An electromechanical quick disconnect package for releasably restraining a load, said package comprising the combination of a first member adapted to be connected to said load,

a second member effective to releasably mate with the first member, said second member being adapted to be connected to a support for carrying the load,

detent means on one of said members moveable between a locked position wherein they engage the othor member and lock said members together and a release position wherein they do not engage said other member and said members are free to separate, keeper moveable between a first position engaging the detent means for maintaining them in the locked position and a second position wherein it disengages said detent means whereby they are free to move to the release position,

spring means efiective to bias the keeper into the second position,

an electrically conductive member coupled to the spring and effective to retain the keeper in the first position, said member having a tension therein which is a function of the spring means and is independent of the load, and

means for circulating an electrical current through said conductive member and heating it until its tensile strength is less than said tension whereby the member breaks and releases the spring for retracting the keeper.

3. An electromechanical quick disconnect package for releasably restraining a load, said package comprising the combination of a first member adapted to be connected to said load,

a second member effective to releasably mate with the first member, said second member being adapted to be connected to a support for carrying the load,

latch means having a first position wherein said members are locked together against the forces of said load and a second position wherein said members are released,

a keeper coupled to the latch means for maintaining the latch means in the first position,

means etfective to bias the keeper into a position Wherein the latch means is free to move to the second position, 7

an electrically conductive member effective to maintain the biasing means and the keeper in position, said biasing means being eifective to produce a predetermined stress in the conductive member, and

means for circulating a current through said member until the temperature thereof reduces its strength to less than said stress whereby the member fails and the biasing means moves the keeper into the release position.

4. An electromechanical quick disconnect package for releasably restraining a load, said package comprising the combination of V a first member adapted to be connected to said load and a second member that mates with the first member and is adapted to be connected to a support for carrying the load,

first latch means having a lock position for securing the two members together and holding said load and having an unlocked position for releasing said members,

a keeper moveable between a first position for maintaining the latch in the locked position and a second position for releasing the latch into the unlocked position,

means for biasing the keeper from the first position to the second position, a

second latch means coupled to the biasing means for maintaining the keeper in the locked position, said second latch means including an electrically conductive member having a stress therein determined by the biasing means, and

means for circulating a current through said conductive member whereby the strength of the member becomes less than said stress at a predetermined level.

5. An electromechanical quick disconnect package comprising the combination of a pair of relatively moveable members, first latch means securing the two members together,

a keeper for maintaining the latch locked,

means biasing the keeper to release said first latch means,

second latch means opposing said biasing means and retaining the keeper in the locked position,

an electrically conductive release in said second latch means, said release having a stress that is a function of the biasing means, and

means for circulating a current through said release whereby the release is heated until its tensile strength is less than said stress.

References Cited UNITED STATES PATENTS 2,139,193 12/1938 Lamothe et a1. 292302 2,583,440 1/1952 Oxley et a1 287-119 2,784,987 3/1957 Corcoran 285319 3,063,032 11/1962 Brush 28533 X 3,159,444 12/1964 Stine 8533 X 3,163,732 12/1964 Abbott et a1 200116 3,201,147 8/1965 De Cenzo 2853'19 X 3,222,088 12/1965 Haeber 2853 19 X CARL W. TOMLIN, Primary Examiner.

35 THOMAS F; CALLAGHAN, Examiner;

Claims (1)

1. AN ELECTROMECHANICAL QUICK DISCONNECT PACKAGE FOR RELEASABLY RESTRAINING A LOAD, SAID PACKAGE COMPRISING THE COMBINATION OF, A FIRST MEMBER ADAPTED TO BE CONNECTED TO SAID LOAD, A SECOND MEMBER EFFECTIVE TO RELEASABLY MATE WITH THE FIRST MEMBER, SAID SECOND MEMBER BEING ADAPTED TO BE CONNECTED TO A SUPPORT FOR CARRYING THE LOAD, A SHOULDER ON ONE OF SAID MEMBERS, A DETENT ON THE OTHER SAID MEMBERS EFFECTIVE TO ENGAGE SAID SHOULDER AND SECURE SAID MEMBERS TOGETHER, A KEEPER WHEN IN THE FIRST POSITION BEING EFFECTIVE SAID KEEPER WHEN IN THE FIRST POSITION BEING EFFECTIVE TO MAINTAIN SAID DETENT IN ENGAGEMENT WITH SAID SHOULDER, SAID KEEPER IN ENGAGEMENT WITH SAID BEING EFFECTIVE TO RELEASE THE DETENT FROM THE SHOULDER, SPRING MEANS COUPLED TO SAID KEEPER TO BIAS IT INTO THE SECOND POSITION, A PLURALITY OF RESILIENT FINGERS COUPLED TO THE SPRING MEANS AND SAID KEEPER FOR MAINTAINING THE KEEPER IN THE FIRST POSITION, SAID SPRING MEANS BEING EFFECTIVE TO PRODUCE A FORCE ON SAID FINGERS TO DEFLECT THEM WHEREBY THE KEEPER IS RELEASE INTO THE SECOND POSITION, AN ELECTRICALLY CONDUCTIVE WIRE SECURED TO SAID FINGERS AND EFFECTIVE TO MAINTAIN THEM COUPLED TO THE SPRING MEANS AND SAID KEEPER, AND WIRE HAVING A TENSION WHICH IS PRODUCED BY SAID SPRING MEANS, AND MEANS FOR CIRCULATING A CURRENT THROUGH SAID WIRE UNTIL ITS TENSILE STRENGTH IS LESS THAN SAID TENSION.

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