US3575482A

US3575482A - Self-adjusting positive locking chassis latch

Info

Publication number: US3575482A
Application number: US830678A
Authority: US
Inventors: Edward Macmaster; Werner Dellith; John L Vander Sande; Paul R Gley
Original assignee: Rex Chainbelt Inc
Current assignee: Rexnord Inc
Priority date: 1969-06-05
Filing date: 1969-06-05
Publication date: 1971-04-20
Anticipated expiration: 1988-04-20

Abstract

A self-adjusting positive locking chassis latch for securely retaining a chassis in housed position in a rack in which a handle assembly on the chassis comprises a primary lever pivotally supported for movement from a release position to a home position in the course of which movement a hook on the primary lever engages a spring-loaded keeper pin to move the chassis home with a controlled locking force and to displace the keeper pin sufficiently relative to the keeper housing to accommodate any interference between the chassis and the rack. A secondary lever is adapted to be moved from a release position to a locking position to move a locking element to a position at which it positively locks interengageable elements, carried respectively by the keeper pin and the keeper housing, in engaged position. A releasable catch arrangement adapted to hold the primary and secondary levers in their home and locking positions prevents the secondary lever from being latched unless the primary lever is already in its home position.

Description

United StatesPatent Edward MacMaster New Milford;

Werner Dellith, kingwood; John L. Vander Sande, North Haledon, NJ.; Paul R. Gley,

[72] Inventors [54] SELF-ADJUSTIN G POSITIVE LOCKING CHASSIS 3,140,905 7/1964 Trotteretal 3,313,586 4/1967 McClintock ABSTRACT: A self-adjusting positive locking chassis latch for securely retaining a chassis in housed position in a rack in which a handle assembly on the chassis comprises a primary lever pivotally supported for movement from a release position to a home position in the course of which movement a hook on the primary lever engages a spring-loaded keeper pin to move the chassis home with a controlled locking force and to displace the keeper pin sufficiently relative to the keeper housing to accommodate any interference between the chassis and the rack. A secondary lever is adapted to be moved from a release position to a locking position to move a locking element to a position at which it positively locks interengageable elements, carried respectively by the keeper pin and the keeper housing, in engaged position. A releasable catch arrangement adapted to hold the primary and secondary levers in their home and locking positions prevents the secondary lever from being latched unless the primary lever is already in its home position.

LATCH 19 Claims, 9 Drawing Figs.

[52] [1.5. CI 312/320, 317/101, 339/75, 339/91 [51] Int. Cl A47b 95/02 [50] Field ofSearch 339/45, 75, 91; 292/(Y); 312/320; 317/101; 21 1/(Inquired) [56] References Cited UNITED STATES PATENTS 2,926,056 2/1960 Newcomer, Jr. et al. 312/320 PATENTEU APR20 l9?! SHEET 1 BF 5 INVENTORS. E dwam Mac/14a s fer Werner De/Ufh JED/m L. Vanda/Sande Paa/ 6 85] H TTORNEYS,

PATENTEU APRZO I97! SHEET 2 [IF 5 PATENTEB APR 20 l97l SHEET 5 UF 5 a; Q O v V m E x 5 WMH I" ll 1 I Hi; J H 111111 l a QR I! I II I Ir- Q Q i uni! III I w Nm N\\ v wfi v v Jbhn ATTORNEYS SELF-ADJUSTING POSITIVE LOCKING CHASSIS LATCH BACKGROUND OF THE INVENTION There are known in the prior art electronic component assembly chassis which are slidably mounted in racks. In the home or housed position of the chassis a multiple pin electrical connector operatively engages a receptacle which receives the pins. Owing to the fact that appreciable force is required to drive the pins into the receptacle chassis of the prior art are provided with levers which swing from release positions to positions at which hooks on the levers engage keeper pins on the rack to drive the chassis home. Moreover, these arrangements of the prior art are provided with catches for releasably holding the lever in the home position.

While many of these chassis latches of the prior art will successfully lock the chassis in the rack under most conditions they do not automatically accommodate any interference between parts on the rack and on the chassis, nor do they have a controlled locking force.

We have invented self-adjusting positive locking chassis latch which will accommodate interference between thechassis and its rack. Our latch not only accommodates interference between the chassis and the rack but also it positively locks the chassis in place after the interference has been accommodated. We provide our latch with means for preventing lockup of the handles unless both levers are latched.

SUMMARY OF THE INVENTION One object of our invention is to provide a self-adjusting positive locking chassis latch which will accommodate some interference between parts carried bythe chassis and by its rack.

Another object of our invention is to provide a selfadjusting positive locking chassis latch which positively locks the chassis in position on the rack after accommodating interference between the chassis and rack carried parts.

Another object of our invention is to provide a selfadjusting positive locking chassis latch which moves the chassis home with controlled locking force.

Another object of our invention is to provide a selfadjusting positive locking chassis latch which prevents lockup of the secondary lever of the latch assembly if the primary lever is not in its home position.

Other and further objects of our invention will appear from the following description.

In general our invention contemplates the provision of a self-adjusting positive locking chassis latch in which the chassis has a latch handle assembly comprising a primary lever pivotally supported for movement from a release position to a home position in the course of which movement a hook on the primary lever engages a pin on a spring-loaded keeper mounted for sliding movement in a keeper housing. Movement of the primary lever to its home position forces the chassis home and causes a spring-loaded keeper to accommodate any interference which might exist. A secondary lever is adapted to be swung from a. release position I to a locking position to move a locking element into a position at which it positively locks interengageable means on the keeper and housing. A releasable catch engages both levers to hold them in their home positions.

BRIEF DESCON OF THE DRAWINGS In the accompanying drawings which form part of the instant specification and which are to be read in conjunction therewith and in which like reference numerals are used to indicate like parts in the various views:

FIG. I is a sectional view of an electrical chassis and rack installation employing our self-adjusting positive locking latch.

FIG. 2 is a fragmentary side elevation of the installation shown in FIG. I showing the details of our latch assembly in closed position with parts broken away and with other parts shown in section.

FIG. 3 is a front elevation of ourself-adjusting positive locking latch assembly taken along the line 3-3 of FIG. 2.

FIG. 4 is a side elevation of our self-adjusting positive locking latch assembly illustrating the positions of the parts when the latch is fully open.

FIG. 5 is a side elevation of our latch with parts broken away and with other parts shown in section illustrating the positions of the parts in an intermediate condition of the latch.

FIG. 6 is a fragmentary sectional view of the form of our latch illustrated in FIGS. 1 to 4 showing a safety action of the catch.

FIG. 7 is a sectional view illustrating an alternative embodiment of our self-adjusting positive locking chassis latch.

FIG. 8 is a sectional view of a still further form of our selfadjusting positive locking chassis latch.

FIG. 9- is a side elevation'with parts broken away of yet another form of keeper assembly of our chassis latch.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIGS. 1 ms of the drawings our selfadjusting positive locking latch assembly indicated generally by the reference character 10 may be applied to a chassis 12 containing various electrical components (not shown) and adapted to be removably received by a rack 14 which may be provided with rails 16 on which the chassis may be slid between a home position at which electrically connecting

elements

18 and 20 are in operative engagement and a position at which the elements are disconnected.

The self-adjusting, self-locking latch assembly 10 includes a keeper assembly indicated generally by the reference character 22 and a handle assembly indicated generally by the reference character 24. The installation of the handle assembly 24 on the front 26 of the chassis 12, the installation of the keeper assembly 22 on the rack 14 and the installation of the

electrical connectors

18 and 20 respectively on the chassis I2 and on the rack 14 all involve certain tolerances. For example, in a particular installation to which our assembly may be applied mounting of the keeper and handle

assemblies

22 and 24 each involves a tolerance. Similarly installation of the

connector elements

18 and 20 each involves a tolerance. In this particular case installation of the components just mentioned may result in a difference in position of chassis 12 in the home position from what one might expect. As will be apparent from the description hereinafterour latch assembly can accommodate this tolerance while at the same time providing a positive locking action when the chassis is home in the rack l4.

The handle subassembly 24 of our latch assembly 10 includes a handle 28 having spaced

sides

30 and 32 and provided with a hand opening 34 by means of which the bandle 28 may be grasped. We secure the handle 28 to the chassis front 26 by any suitable means known to the art such as for example as by rivets or bolts or the like (not shown). A pivot pin 36 extending between the

sides

30 and 32 adjacent the lower portion of handle 28 pivotally supports a primary lever 38 for swinging movement between a released or open position and an actuated or closed position whereat the handle 38 is disposed between the

sides

30 and 32.

The ends of pin 36 extend outwardly beyond the

sides

30 and 32 pivotally to receive the

sides

40 and 42 of a secondary lever 44 adapted to swing between an open position away from the handle 28 and a closed position at which the

sides

40 and 42 are adjacent the

sides

30 and 32 of the handle 28.

We provide the handle assembly 24 with a catch 46 pivotally supported by a spring pin 48 extending between the

handle sides

30 and 32 at the top of the handle adjacent the panel 26. A spring 50 extending between-a recess 52 in a boss 5s at the top of the handle 28 and another recess 56 in the catch 46 normally urges the catch to rotate in a counter clockwise direction as viewed in FIG. 2. When the primary handle 38 is in its home position a hook 58 on the catch 46 engages in a recess 60 in an end of handle 38 to hold the handie in that position. To permit the catch 46 to be actuated to release the primary handle 38 we form the catch 46 with a thumbpiece 62 extending outwardly through an opening 64 in secondary handle 44 to a position at which the thumbpiece is accessible to the user.

A leaf spring 66 carried by the catch 46 supports a secondary lever locking pin 68 having ends of reduced diameter which extend outwardly through respective slots 70 in

sides

30 and 32. This pin 68 rides into notches 72 in the

sides

40 and 42 of the secondary lever 44 when that lever is in its home position. An enlarged boss 69 located between the ends of pin 68 rests in a recess 74 in the catch 46. This construction is such that the ends of pin 68 cannot ride into notches 72 unless the primary lever is in its home position. We form catch 46 with a recess carrying a spring 76 which initiates movement of the levers to the released position when the actuator 46 is operated in a manner to be described.

The keeper assembly 22 of our latch assembly includes a generally cylindrical housing 78 which receives a piston 80 screwed onto a hollow rod- 82 which extends out of housing 78 through an opening 84 to

bifurcations

86 and 88 forming part of the keeper. A coil spring 90 bears between the endof housing 78 formed with opening 84 and the piston 80 normally to urge the keeper and the keeper pin 92 carried thereby to the right as viewed in FIGS. 2, 4 and 5. We employ any suitable means such for example as a bolt 94 or the like to secure a lug 96 on housing 78 to the back of the rack face to mount the keeper assembly 22 on the rack.

We form the lower end of primary lever 38 with a recess 98 having a hook 100 at one side thereof. With the primary lever 38 in its open position as the chassis 12 approaches its home or housed position keeper pin 92 strikes the base of recess 98 to begin to swing the lever 38 upwardly. Operation of the lever 38 to move it fully into its home position exerts a force-tending to draw the keeper pin 92 to the left as viewed in FIGS. 2, 4 and against the action of spring 90 which may be preloaded to a desirable force. It will be understood that with the primary lever 38 moved fully into its home position the hook 58 of catch 46 enters into recess 60 to hold the lever in its home position. If owing to the tolerances involved the handle 36 could not normally be moved into its home position when the chassis is housed any excess movement required of the handle will be taken up by compression of spring 90.

In the form of our latch assembly illustrated in FIGS. 1 to 5 piston 80 carries a plurality of locking fingers 102 which extend axially of the housing 78. The outer surfaces of the fingers 102 are provided with serrations 104 adapted to engage with annular serrations 106 formed in the inner surface of housing 78 for a distance along its length from the open end thereof at the right as viewed in FIG. 2. In the particular embodiment which we have shown there may be for example eight fingers 102. It will be appreciate that the fingers 102 move with keeper pin 92 and that the location along the length of housing 78 at which teeth 104 engage the serrations 106 is determined by the tolerances of the installation.

We provide our latch assembly with means for locking the fingers 102 in the positions at which they engage the serrations 106 in response to the operation of the primary lever pointed out hereinabove. A rod 108 extends from a head 110 through the bore 112 of keeper rod 82 to a locking pin 114 which extends outwardly through slots 116. We slidably mount a locking cone or cam 118 on the rod 108 between head 110 and a stop pin 120. A coil spring 122 extending between head 110 and the cone 118 loaded to a substantially lower load than spring 90 is adapted so as normally to force the cone 118 into engagement with pin 120. Another spring 124 bears between keeper rod 82 and the pin 120 nonnally to urge the entire assembly of the rod 108, pin 114 and cone 118 to the right as viewed in FIGS. 2, 4 and 5. We form the

respective sides

40 and 42 of the secondary lever with hooks 126 which are adapted to engage pin 114 and to move it from the right end of slots 116 to the lefi ends when the secondary lever is moved from its released to its locking position in a manner to be described.

Referring now to FIG. 7 we have illustrated an alternative form of our latch assembly in which the

keeper comprising bifurcations

86 and 88 carrying pin 92 has a solid shaft 128 extending into a housing 130 and receiving a piston head 132 at a location intermediate its ends. Spring normally urges head 132 to the right. We form head 132 with a plurality of fingers 134 adapted to be cammed into engagement with the inner surface of the housing in a manner to be described. The locking element of this form of our assembly includes a conical member 136 slidably received on an extension 138 of shaft 128 and normally urged to the left as viewed in FIG. 7 by a spring 140. In this form of our invention hooks 126 are received in slots 142 formed in the ends of rods 144 extending through bores 146 in housing 130 to a yoke 148 against which spring bears. After fingers 134 have been positioned in response to operation of the primary lever the secondary lever is actuated to cause the yoke to drive the locking cone 136 through the medium of spring 140 to lock the fingers.

Referring now to FIG. 8 in a still further form of our latch assembly the piston head 80 has extensions 150 formed with pockets 152 for receiving balls 154. The locking cone 156 normally is urged to the left as viewed in FIG. 8 against a stop ring 158 by means of a spring 160. After the balls 154 are first positioned by operation of the primary lever operation of the secondary lever moves the locking cone 156 to a position at which balls 154 are wedged between the cone and a conical surface 162 at the open end of housing 78.

Considering the operation of the form of our self-adjusting locking assembly shown in FIGS. 1 to 5 with the primary and secondary levers fully open the position of the parts of the keeper and locking mechanism 22 will be shown in FIG. 4. From that position once the chassis 12 has been moved to a position adjacent its home position the primary lever first is pivotedjn a clockwise direction to bring its hook 100 into engagement with pin 92. As the lever is moved to its home position head 80 acts on spring 90 to tend to draw the chassis fully into its home position. If owing to tolerances of the assembly the chassis would not otherwise be able to be driven completely home spring 90 will be compressed until the primary lever is latched by the book 58. After the primary lever has thus been moved to its home position the fingers 102 will be correspondingly located at a certain position along the length of the serrations 106. We have illustrated this relative position of the parts in FIG. 5 as if there were some interference between the chassis and the rack or between the

connectors

18 and 20 as would otherwise prevent the primary lever from being moved to the fully closed position.

Next, the secondary lever 44 is rotated in a clockwise direction from the position shown in FIG. 5 to the position shown in FIG. 2. As that movement takes place hook 126 engages pin 114 to draw the locking cone 118 into engagement with fingers 102 through the medium of spring 122 to lock the fingers in place. When the secondary lever 44 is in its home position the ends of pin 68 drop into recesses 72 to lock that lever in position. It will be noted as shown in FIG. 6 that if for any reason the primary lever is not fully'home the secondary lever will not be latched in place. Thus our assembly is so arranged that the secondary lever cannot be latched in position unless the primary lever has already been locked in. It will be noted also that our arrangement permits the secondary lever to be locked without disturbing the primary lever.

To release the latch assembly thumbpiece 62 is operated to move the latch 46 in clockwise direction against the action of spring 50. Both levers are released at once. When that occurs spring 124 moves the cone and rod 108 to the right out of engagement with the fingers 102. Next, the spring 90 moves the keeper piston and fingers 102 to the limit of their movement with the serrations 104 ratcheting over serrations 106 until the assembly is completely free.

The operation of the other forms of our invention will readily be apparent from the description hereinabove of the embodiment of FIGS. 1 to 6.

In FIG. 9 we have shown yet another form of keeper assembly indicated generally by the reference character 164 which may be used with our chassis latch. The assembly 164 houses the piston 80 which is connected by a rod 82 to a somewhat modified form of keeper 168 having bifurcations 1170 which receive the pin 92. The operation of the spring loaded keeper M8 is substantially the same as is that of the keeper shown in FliGS. I to 6 in that it is spring loaded for movement to the right as viewed in the figure. We provide the end of the housing 168 to the left in FIG. 9 with a notch or recess 172 for receiving the base of keeper 168 to prevent rotation thereof relative to housing 166 when the pin 92 is not engaged by the hook 100. In this way we ensure that the keeper will be oriented for engagement by the hook when the latch assembly is operated.

The assembly 164 further includes the locking rod 108 having the head 110 as well as the pin 114 which extends through slots 116 in keeper 168 to permit the ends of the pins to be engaged by hook 126 of the secondary lever. As in the form of our latch shown in FIGS. 1 to 6 movement of rod 108 to the left as viewed in FIG. 9 causes the locking cone 118 to engage the fingers 102. In the form of our device shown in FIG. 9 as distinguished from that shown in FIGS. 1 to 6 rather than forming the locking serrations 104 directly on the wall of housing 166 we provide the housing with a separate bushing 174 on which the serrations 176 which may be screw threads are formed. It will be appreciated that owing to the fact that the serrations 104 on fingers I02 ratchet ,over the serrations 104 or 176 the member in which the serrations are formed must be made of a relatively hard material such as steel. The separate bushing construction illustrated in FIG. 9 permits us to make the housing 166 of a relatively softer material if desired while at the same time providing a surface of a relatively hard material in which the locking serrations are formed.

It will be seen that we have accomplished the objects of our invention. We have provided a self-adjusting positive locking chassis latch which will accommodate tolerances inherent in the assembly of the parts of the device. While accommodating these tolerances our latching assembly provides positive locking action. Our arrangement is such that the locking lever cannot be latched in the locked position unless the operating lever also is latched.

It will be understood and that certain features subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of our claims. It is further obvious that various changes may be made in details within the scope of our claims without departing from the spirit of our invention. It is, therefore, to be understood that our invention is not to be limited to the specific details shown and described.

We claim:

1. A latch assembly for securing body in a home position on a support including in combination, first interengageable means on said body and on said support for moving said body into said home position, said first interengageable means comprising a spring-loaded keeper and a latching member mounted for movement between a release position out of engagement with said keeper and a latching position in engagement with said keeper at which said body is in said home position, second interengageable means on said body and on said support mounted for movement between release positions and engaged positions and means responsive to movement of said second interengageable means from said release positions to said engaged positions for positively locking said keeper in the position which it occupies following operation of said first interengageable means.

2. A latch assembly as in claim I including means for releasably retaining said latching member in its latching position.

3. A latchassembly as in claim including common means for releasably retaining said latching member in locking position and for releasably retaining said second interengageable means in engagement with the support.

4. A latch assembly as in claim 1 including a housing mounting said keeper for sliding movement and a spring carried by said housing for urging said keeper to move in a direction toward the home position of said body.

5. A latch assembly for securing a body in a home position on a support including in combination, a housing on said support, a keeper mounted for sliding movement on said housing, a spring normally urging said keeper in a direction toward the home position of said body, a primary lever mounted for movement on said body between a release position and a latching position, interengageable actuating means on said primary lever and on said keeper for moving said body into said home position in response to movement of said primary lever from said release position to said latching position, interengageable locking means carried by said housing and by said keeper, a secondary lever mounted on said body for movement from a release position to a locking position and means responsive to movement of said secondary lever to its locking position for retaining said interengageablelocking means in locked position.

6. An assembly as in claim 5 in which said housing is formed with a bore, said interengageable locking means comprising friction spring fingers on said keeper located in said bore.

7. An assembly as in claim 5 in which said housing is formed with a bore and in which interengageable locking means comprise spring fingers carried by said keeper in said bore, serrations on said fingers and serrations in said housing bore for engagement by said finger serrations and in which said means for locking said interengageable locking means comprises means for camming said finger serrations into engagement with said bore serrations.

8. An assembly as in claim 5 in which said housing is formed with a bore and in which said interengageable locking means comprise friction fingers carried by said keeper within said bore and in which said means for locking said interengageable locking means comprises means for camming said friction fingers into engagement with said bore.

9. An assembly as in claim 5 in which said housing is formed with a bore and in which said interengageable locking means comprise a rolling element supported by said keeper in said bore, and in which said means for locking said interengageable locking means comprises means for wedging said element into engagement with said bore.

10. An assembly as in claim 5 including a common catch for releasably holding said primary lever in its locking position and for releasably holding said secondary lever in its locking position.

11. An assembly as in claim 5 including a catch, means mounting said catch on said body for movement between released and operative positions, first interengageable means on said catch and on said primary lever for holding said primary lever in latching position, second interengageable means on said secondary lever and on said catch for holding said secondary lever in locking position, said first interengageable means comprising means for preventing engagement of said second interengageable means until said primary lever is fully in said latching position.

12. An assembly as in claim 5 in which said housing is formed with a bore, said interengageable locking means comprising elements carried for movement with said keeper in said bore, and in which said means for locking said locking means comprises a rod slidable in said housing and a cam carried by said rod for camming said elements toward the wall of said bore.

13. An assembly as in claim 5 including means for restraining said keeper and said housing against relative movement in the home position of said keeper.

M. An assembly as in claim 5 in which said interengageable locking means comprise resilient fingers carried by said keeper, serrations onsaid fingers and serrations on said housing for engagement by said finger serrations.

15. An assembly as in claim 14 in which said locking means comprise a separate bushing in said housing, said housing serrations being formed on said bushing.

16. A latch assembly for securing a body in a home position on a supportincluding in combination, a housing on said support, a keeper slidably supported on said housing, a spring for biasing said keeper in a direction toward the home position of said body, said housing being formed with a bore, lockable elements carried by said keeper in said bore, a locking rod, a cam on said rod, means mounting said rod on said housing for movement between a release position and a locking position at which said cam moves said locking elements into engagement with the wall of said bore, means biasing said rod toward said release position, a primary lever, means mounting said primary lever on said body for movement between a release position and a latching position, interengageable means on said primary lever and on said keeper for moving said body to its home position in response to movement of said primary lever to its latching position, a secondary lever, means mounting said secondary lever on said body for movement from a release position to a locking position, and interengageable means on said secondary lever and on said locking rod for moving said rod to its locking position in response to movement of said secondary lever to its locking position.

17. An assembly as in claim 16 in which said cam is mounted for sliding movement on said locking rod, a stop on said rod and a spring for biasing said cam into engagement with said stop.

18. An assembly as in claim 16 including a catch, means mounting said catch on said body for movement between released and operative positions, first auxiliary interengageable means on said catch and on said primary lever for holding said primary lever in latching position, second auxiliary interengageable means on said catch and on said secondary lever for holding said secondary lever in locking position, said first auxiliary interengageable means comprising means for preventing engagement of said second interengageable means until said primary lever is fully in said latching position.

19. A latch assembly for a reciprocable member including in combination a support for the reciprocable member, a keeper, means carried by the support for floatingly mounting said keeper, said mounting means including biasing means for biasing said keeper to move said reciprocable member toward a home position, a latching lever pivotally mounted on said reciprocable member, one end of said lever provided with means for engaging said keeper whereby pivotal movement of said lever will move said reciprocable member toward home position, means for retaining said latching lever in the home position of said reciprocable member, means for immobilizing said keeper after movement of said latching lever to home position, and means carried by said reciprocable member for retaining said immobilizing means in keeper-immobilizing position.

mg UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 8 Dated April 20, 1971 I fl Edward MacMaster; Werner Dellith; John L. Vander Sande; and Paul R. Gley It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 5, line 56, the article ashould be inserted after "securing".

Column 5, line 74, after "claim" the numeral --lshould be inserted.

Signed and sealed this lath dam od July 1971*.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. WILLIAM E. SGHUYLER,JR. Attesting Officer Commissioner of Patents

Claims

1. A latch assembly for securing body in a home position on a support including in combination, first interengageable means on said body and on said support for moving said body into said home position, said first interengageable means comprising a springloaded keeper and a latching member mounted for movement between a release position out of engagement with said keeper and a latching position in engagement with said keeper at which said body is in said home position, second interengageable means on said body and on said support mounted for movement between release positions and engaged positions and means responsive to movement of said second interengageable means from said release positions to said engaged positions for positively locking said keeper in the position which it occupies following operation of said first interengageable means.

2. A latch assembly as in claim 1 including means for releasably retaining said latching member in its latching position.

3. A latch assembly as in claim including common means for releasably retaining said latching member in locking position and for releasably retaining said second interengageable means in engagement with the support.

5. A latch assembly for securing a body in a home position on a support including in combination, a housing on said support, a keeper mounted for sliding movement on said housing, a spring normally urging said keeper in a direction toward the home position of said body, a primary lever mounted for movement on said body between a release position and a latching position, interengageable actuating means on said primary lever and on said keeper for moving said body into said home position in response to movement of said primary lever from said release position to said latching position, interengageable locking means carried by said housing and by said keeper, a secondary lever mounted on said body for movement from a release position to a locking position and means responsive to movement of said secondary lever to its locking position for retaining said interengageable locking means in locked position.

14. An assembly as in claim 5 in which said interengageable locking means comprise resilient fingers carried by said keeper, serrations on said fingers and serrations on said housing for engagement by said finger serrations.

16. A latch assembly for securing a body in a home position on a support including in combination, a housing on said support, a keeper slidably supported on said housing, a spring for biasing said keeper in a direction toward the home position of said body, said housing being formed with a bore, lockable elements carried by said keeper in said bore, a locking rod, a cam on said rod, means mounting said rod on said housing for movement between a release position and a locking position at which said cam moves said locking elements into engagement with the wall of said bore, means biasing said rod toward said release position, a primary lever, means mounting said primary lever on said body for movement between a release position and a latching position, interengageable means on said primary lever and on said keeper for moving said body to its home position in response to movement of said primary lever to its latching position, a secondary lever, means mounting said secondary lever on said body for movement from a release position to a locking position, and interengageable means on said secondary lever and on said locking rod for moving said rod to its locking position in response to movement of said secondary lever to its locking position.