US3074577A

US3074577A - Ball latch and drive mechanism

Info

Publication number: US3074577A
Application number: US92058A
Authority: US
Inventors: Donald M Barrus
Original assignee: North American Aviation Corp
Current assignee: North American Aviation Corp
Priority date: 1961-02-27
Filing date: 1961-02-27
Publication date: 1963-01-22
Anticipated expiration: 1980-01-22

Description

Jan. 22, 1963 D. M. BARRus BALL LATCH AND DRIVE MECHANISM 5 Sheets-Sheet 1 Filed Feb. 27, 1961 ATTORNEY Jan. 22, 1963 D. M. BARRUS BALL LATCH AND DRIVE MECHANISM 5 Sheets-Sheet 2 Filed Feb. 2'7, 1961 S MU R R A B M L A N O D ATTO RNEY Jan. 22, 1963 D. M. BARRUS BALL LATCH AND DRIVE MECHANISM 5 Sheets-Sheet 3 Filed Feb. 27, 1961 INVEN TOR.

DONALD M. BARRUS ATTORNEY Jan. 22, 1963 D. M. BARRUS 3,074,577

BALL LATCH AND DRIVE MECHANISM Filed Feb. 27, 1961 s Sheets-Sheet 4 HIM ss v '89 INVENTOR.

ATTORNEY DONALD M. BARRUS Jan. 22, 1963 D. M. BARRUS BALL LATCH AND DRIVE MECHANISM 5 Sheets-Sheet 5 Filed Feb. 2'7, 1961 t$--ili INVENTOR.

DONALD M. BARRUS ATTORNEY plug.

EEMS?! Patented Jan. 22, 1963 &

3,074,577 BALL LATCH AND DRIVE MECHANISM Donald M. Barrus, Canoga Park, Calih, assignor to North American Aviation, Inc. Filed Feb. 27, 1961, Ser. No. 92,058 9 Claims. (Cl. 214-658) The present invention is directed to a connector and more particularly a quick disconnect ball latch and drive mechanism.

In the nuclear reactor art the control and safety rods must be connected to the lifting mechanism by a connector which is a simple, fail-safe, compact unit and which will function properly in high temperature environments and not require complicated indexing and aligning mechanisms. Prior art mechanisms generally require ro tational indexing as well as axial alignment before the grapple or hook is in a proper position to engage the element to be lifted. Further, any malfunction in the lifting and lowering mechanism must be fail-safe so that the rod will be dropped into its control position as a result of such a malfunction.

It is therefore the primary object of the present invention to provide a simple, inexpensive, fail-safe connector for use on control or safety rods or similar devices.

It is a further object of the present invention to pro- Vide a safety or control rod drive mechanism and latch wherein the rod may be dropped at any point in its operation.

It is another object to provide a connector or latch which has no splines or close tolerances, is reliable, selfaligning, and self-indexing.

It is a further object to provide a drive and latch mechanism in which the drive is located within the shield plug of a reactor.

These and other objects of the present invention will be more apparent from the following detailed description and drawings, hereby made a part hereof, in which:

FIGURE 1 is a partially sectioned view of the drive mechanism of the present invention;

FIGURE 2 is a detail sectional view along line 2-2 of FIG. 1;

FIGURE 3 is a partially sectioned perspective view of the connector or latch of the present invention;

FIGURE 4 is a sectional view of the device of KG. 3; and

FIGURE 5 is a sectional view along line 55 of FIG. 4.

The preferred embodiment of the drive mechanism and cable drum assembly utilized for actuating the ball latch mechanism of the present invention is shown in FIGS, 1 and 2. The drive mechanism and cable drum assembly are maintained within a thimble which has a lower supporting shoulder 11 and which is supported at its top (not shown) in the reactor loading face of the top shield Within the thimble 10 is a reversible motor drive 12 mounted on a plate 13 which is integrally connected to an upper gear box mount 14 of the gear box 15. The gear box 15 has a lower gear box mount 16 to which shield plugs 17 are attached by cap screws or other removable means. The lower gear box mount 16 is supported by a miter ear box assembly 18 which is supported on the drum frame 19, in which is mounted the drum assembly described hereinafter. The drum frame 19 consists of a drum frame body 26 (see FIG. 2) and a drum frame side plate 21. The side plate 21 and body are integrally connected to a sleeve 22 which is welded to the upper cable guide assembly 23 which has a shoulder 24 engaging the thirnble lower support shoulder 11 so that the entire cable drum assembly and drive mechanism is supported by the thirnble 1t The reversible motor drive 12 has a shaft 28 connected through a coupling 29 to the input gear box 15, which has its output shaft 3% connected through a slip clutch 31 to the input shaft 32 of the miter gear box 18. The input shaft 32 is connected to the drive miter gear 33 which meshes with upper miter gear 34 and lower miter gear 35. Miter gears 34 and 35 are mounted for rotation on shaft 36 journaled in the miter gear box assembly 18 and have upper and

lower sprocket gears

37 and 38, respectively. The upper sprocket gear 37 is connected through a sprocket chain 39 to upper cable drum drive sprocket 40 which is integrally connected to shaft 41 by pin 42. The shaft 41 is mounted for rotation in drum frame 19 with bushing 43 at one end and is integrally connected at the other end to the upper cable drum 44. The upper cable drum 44 is of hollow construction and has its outer extremities in rotatable engagement with bearings 46, which are mounted on extensions 47 of the drum frame body 20. Within the hollow central portion 48 of the drum 44- is mounted a position indicator potentiometer 49. The position indicator has a drive shaft 51 integrally connected to arm 52 which, in turn, is integrally connected to pin 53, which extends into drum 44 so that upon rotation of the drum 44 pin 53 functions as a crank to rotate shaft 51 and change the position of the pickup in the potentiometer of position indicator 49. The upper cable drum 44 has a cable 55 wound on its outer surface and is integrally connected to the end of cable 55.

Lower sprocket gear 38 meshes with sprocket chain 57 which passes through chain adjuster 58 (see FIG. 1) and I meshes with lower cable drum drive sprocket 59 which is integrally attached to shaft 66 by pin 61. The shaft 6%) is mounted for rotation in bushings 62 which are supported in drum frame body 2% and drum frame side plate 21. Integrally connected with the shaft and rotating therewith is clutch plate 63 which has a slot 64 which extends through about a 90 degree are and in which a pin 65 is slidable to engage either end of the slot, as is described in more detail hereiinafter. The pin 65 in integrally mounted in index plate 66 which is connected by cap screw or other means to the drum 67. The

index plate 65 has 3 apertures 63 into which balls 69 are forced during normal operation. The balls 69 are movable axially wlthin the clutch plate 63 and are forced into engagement with index plate 66 by bushings 7% which drum pawl or dog (see FIGURE 1) 77 which is actuated in the radial direction, e.g. by a spring, not shown, when the last loop of cable 76 is unwound from the drum 67. This pawl 77 engages spring-biased switch 78 which stops the drum 67 from rotating to reindex the index plate 66 and the balls 69, and after reindexing turns off the reversible motor drive 12, as explained in more detail hereinafter in the description of the operation of the device.

Cables

55 and 76 pass downwardly through the upper cable guide assembly in which idler and guide pulleys 7?, which are mounted normal to each other, are located and pass into guide tubes 8%, which extend downwardly through the shield plug 81 and terminate just above the upper position of the ball latch. Also extending downwardly through the shield plug 81 is rod 82 which is contacted by the upper surface of the ball latch when it has reached its highest position and is moved upwardly by the ball latch, and by forcing switch actuator 83 to contact microswitch ale-energizes the reversible motor drive to limit the upward movement of the 'ball latch.

The ball latch is shown in FIG. 3 and is supported by

cables

55 and 76 which have Weights 36 at their lower extremities and are connected through socket and fork connectors 87 which are pivotally mounted on pins 88 to the body 39 of the ball latch.

The body of the ball latch has a hemispherical or rounded bottom surface 90 through which an opening 91, preferably cylindrical, passes. The opening 91 forms two

apertures

92 and 93 separated by opposed extensions or shoulders 95 of the bottom spherical surface 90, the shoulders being separated by a slot 94. This arrangement is herein referred to as a keyhole slot. The element to be raised or lowered is preferably provided with a spherical ball or other engaging element 97 mounted on a pin 98 which is integrally connected to the element 99 to be raised or lowered. The ball 97 is of such size as to be freely slidable within the keyhole slot and supported by the bottom extensions 95 of the ball latch body 89. In this manner a break in either cable will disconnect the body 89 from the engaging element 97 and allow the element 99 to drop. FIGURE 3 shows the ball latch in its disconnected position, while FIGURE 4 shows the ball latch in its connected position.

In operation of the device the ball latch is assumed to 'be in the position shown in FIGURE 4, that is, connected to the element 99. The reversible motor drive 12 is energized in either direction and the element 99 is moved up or down through the

cables

55 and 76 on the cable drum assembly. The pin 65 is at this time in the position shown in phantom at 100 (see FIG. 1). If it is desirable to drop the element 99, as for example in a scram condition in a reactor, the scram solenoid 75 is deenergized, lever 73 moves outwardly as shown in FIGURE 2, thereby allowing pressure plate 71 to move outwardly and the balls 69 to fall out of engagement with the index plate 66. Since there is then no connection between the shaft 6%) through plate 63 and the drum 67, the cable 55 will, under the force of gravity, move the cable drum 67 through an arc of about 90 degrees until the pin 65 engages the end 101 of slot 64, as shown in FIG. 1. This allows-the ball latch body 89 to assume the tilted or rotated position shownin FIG. 3, in which case the ball 97 will slide off the extensions or shoulders 95 and allow the element 99 to drop under its own weight. This operation can take place regardless of the relative position between the ball latch body and the cable drum assembly.

In order to re-enegage the ball latch body 89 with the ball 97 of the element 99, the reversible motor drive and scram solenoid are energized and through the

sprocket chains

57 and 39 the drum 44 is unwound and cable is lowered. Since there is no connection between the clutch plate 63 and the index plate 66, the lower cable drum is disconnected from its drive sprocket 59 and, driven by the force of gravity, unwinds as the cable drum 44 unwinds. As the drum 67 reaches its unwound position, the pawl 77 engages the spring-biased switch 78 and prior to tie-energizing the reversible motor drive, is stopped before the sprocket 59 is stopped so that the pin '65 is moved through the length of the slot from end 101 to position 100 where it engages the other end of the lot, :at which time the clutch is re-engaged and there is sufficient driving force from the sprocket 59 to actuate the switch 78 to 'deenergize the reversible'rnotor drive i2.

As the pin 65 is moved from position 101 to position 10%), the latch body 89 is moved from its tilted position (FIG. 3) to its horizontal position (FIG. 4) and the keyhole slot engages the ball 97 so that the element 99 may now again be moved in its axial direction.

.Although a particular embodiment of the present invention has been described, various modifications will be apparent to those skilled in the art. Therefore, the present invention is not limited to the specific embodiment disclosed but only by the appended claims.

What is claimed is:

1. A latch mechanism comprising in combination a latch body and an element adapted to be disconnectably supported by said body, said latch body having a rounded surface portion at one end, a keyhole slot traversing said portion, said keyhole slot defining a pair of apertures in said portion adapted to pass said element, said apertures being separated by two opposing inwardly extending shoulders on said body, said shoulders being adapted to engage said element.

2. A latch mechanism comprising in combination a latch body and anvelernent, said element having a ball connector at one end of its longitudinal axis, said ball connector being adapted to be disconnectably supported by said body, said body having a concave surface at one end, a keyhole slot traversing said surface in a direction normal to said axis and defining two apertures in said concave surface adapted to pass said bail, a pair of inwardly extending shoulders on said surface separating said apertures, said shoulders being adapted to engage the bottom surface of said ball, thereby supporting said element.

3. A latch mechanism comprising in combination a latch body and an element adapted to be disengageably supported by said body, means connected to one end of said body for rotating said body from a first position to a second position, the other end of said body having a rounded surface portion, a keyhole slot in said portion defining a pair of apertures adapted to pass said clement, said apertures being separated by two opposing inwardly extending shoulders on said body, said shoulders being adapted to engage said element when said body is in said first position and to disengage said element when said body'i-s rotated to said second position.

4. A latch mechanism comprising in combination a latch body and an element, said element having a ball connector at one end of its longitudinal axis, said ball connector being adapted to be disconnectably supported by said body, said body having a concave surface at one end, a keyhole slot traversing said surface in a direction normal to said axis and defining two apertures in said concave surface adapted to pass said ball, a pair of inwardly extending shoulders on said surface separating said apertures, said shoulders being adapted to engage the bottom surface of said ball, thereby supporting said element, and means for rotating said body to a plurality of positions, one of said positions placing said shoulders adjacent said ball, and another'of said positions placing one of said apertures adjacent said ball.

5. A latch mechanism comprising in combination a latch body, an element, said element having a ball connector at one end adapted to be disconnectably supported by said body, a keyhole slot traversing said body defining two apertures adapted to pass said ball and shoulder means for engaging said ball, said shoulder means being located between said apertures, a first support member and a second support member, said support members being connected to said body at points opposite said apertures, means connected to said support members for moving said support members, and means for releasing one of said support members from said moving means.

6. A lift mechanism comprising in combination a latch body and an element adapted to be disconnectably supported by said body, said latch body having a rounded bottom surface, a keyhole slot traversing said bottom surface and defining a pair of apertures in said surface adapted to pass said element, said apertures being separated by opposing inwardly extending shoulders, said shoulders being adapted to engage said element when said shoulders are in a first position, means for rotating said body from a first position to a second position, said means including a first and second suspension element, a first and second drum connected to said first and second suspension elements, respectively, means for driving both said drums to move said body along an axis, and means for moving one of said drums relative to the other of said drums so that said body is tilted from said first position to said second position.

7. A lift mechanism comprising in combination a latch means and latch drive means for moving said latch means along an axis, said latch means having a latch body, said latch body having a rounded lower surface and a keyhole slot traversing said lower surface in a direction normal to said axis, a ball connector adapted to be engaged by said keyhole slot, said keyhole slot having a pair of shoulders adapted to engage the bottom surface of said ball, a first cable and second cable, said first and second cable being connected to said latch body at points opposite said lower surface and spaced on opposite sides of said shoulders, said latch drive mechanism having a first and second drum connected to said first and second cable, respectively, means for rotating said drums to wind and unwind said cables, means for selectively rotating one of said drums with respect to the other of said drums so that one side of said latch body is lowered With respect to the other, whereby said ball is allowed to slide ofi" said shoulders, and means reindexing said drums at the lowest position or" said latch means so that said latch body is rotated to re-engage said ball.

8. A drive mechanism comprising in combination a first rotatable drum, a second rotatable drum, drive means connected to said drums, said drums having an indexed position with respect to each other, means for selectively rotating said second drum through a predetermined arc with respect to said first drum to an unindexed position, means stopping the rotation of said second drum while rotating said first drum through said predetermined are for reindeXing said second drum.

9. A drive mechanism comprising in combination a first rotatable drum, a second rotatable drum, means for rotating said first drum, clutch means, said clutch means being connected between said rotating means and said second drum, means for actuating said clutch means to disconnect said second drum from said drive means, means for rotating said second drum through a predetermined arc with respect to said first drum, and means for stopping the rotation of said second drum while rotating said first drum through said predetermined arc.

References Cited in the file of this patent UNITED STATES PATENTS 1,019,500 Libby Mar. 5, 1912 2,645,455 Rowe July 14, 1953 2,742,307 Elsner Apr. 17, 1956 2,955,852 Janssen Oct. 11, 1966-

Claims

6. A LIFT MECHANISM COMPRISING IN COMBINATION A LATCH BODY AND AN ELEMENT ADAPTED TO BE DISCONNECTABLY SUPPORTED BY SAID BODY, SAID LATCH BODY HAVING A ROUNDED BOTTOM SURFACE, A KEYHOLE SLOT TRANSVERSING SAID BOTTOM SURFACE AND DEFINING A PAIR OF APERTURES IN SAID SURFACE ADAPTED TO PASS SAID ELEMENT, SAID APERTURES BEING SWPARATED BY OPPOSING INWARDLY EXTENDING SHOULDERS, SAID SHOULDERS BEING ADAPTED TO ENGAGE SAID ELEMENT WHEN SAID SHOULDERS ARE IN A FIRST POSITION, MEANS FOR ROTATING SAID BODY FROM A FIRST POSITION TO A SECOND POSITION, SAID MEANS INCLUDING A FIRST AND SECOND SUSPENSION ELEMENT, A FIRST AND SECOND DRUM CONNECTED TO SAID FIRST AND SECOND SUSPENSION ELEMENTS, RESPECTIVELY, MEANS FOR DRIVING BOTH SAID DRUMS TO MOVE SAID BODY ALONG AN AXIS, AND MEANS FOR MOVING ONE OF SAID DRUMS RELATIVE TO THE OTHER OF SAID DRUMS SO THAT SAID BODY IS TILTED FROM SAID FIRST POSITION TO SAID SECOND POSITION.