Latching mechanism

A latching mechanism for a cab which is tiltably mounted to the chassis of a vehicle. The cab is normally disposed over the engine of the vehicle in a first or lowered position and is pivotally attached to the chassis at its forward end for movement through 90.degree. to a second or raised position. The latching mechanism securely locks the cab in the lowered position and includes interengaging latching elements attached to the underside of the cab and to the chassis of the vehicle. The receiving means includes a ball detent arrangement actuated by means of a hydraulically powered cam sleeve. The ball detents move radially between a first or unlocked position and a second and locked position. When in the locked position, the detents engage shoulder portions on one latching element to securely lock the cab to the chassis.

BACKGROUND OF THE INVENTION 
This invention relates to a latching mechanism which may be put to a number 
of different uses but which is disclosed herein as being primarily useful 
with vehicles wherein an operator cab is mounted over the engine and is 
tiltable from a first or lowered position through approximately 90.degree. 
to a second or raised position to expose and permit access to the engine 
when required. 
In one form of this invention the latching mechanism includes a latching 
element affixed to one side of a member to be locked into position and a 
latching member receiving means affixed to a surface of a member to which 
it is to be secured. The latching element receiving means includes a 
cam-actuated detent arrangement whereby the detents will move radially 
from a first or unlocked position to a second or locked position in 
engagement with detent receiving means on the latching element to firmly 
secure the latching element and the member to which it is attached. There 
are many latching mechanisms in the prior art which employ a cam-actuated 
detent arrangement. U.S. Pat. No. 3,764,172 to Standke dated Oct. 29, 
1971, and entitled LATCH ASSEMBLY, discloses a detent type arrangement in 
a latching mechanism. Also, there is a fair amount of activity in the 
prior art in the area of latching mechanisms for tilting cab vehicles. 
See, for example, U.S. Pat. No. 3,667,566 to Hopkins, dated June 6, 1972, 
entitled RELEASABLE CONNECTOR TICULARLY FOR TILT CAB VEHICLES. The 
latching mechanism of this invention constitutes an improvement over 
mechanisms such as those disclosed in the aforementioned patents. 
SUMMARY OF THE INVENTION 
The latching mechanism of this invention is useful in any number of 
situations wherein it is desired to secure one member to another. The 
latching mechanism is particularly useful in tilting cab vehicles and will 
be described in the context of such use for purposes of description. 
In a preferred embodiment, a latching element is secured to the upper 
surface of a chassis on each side thereof at the rear end portion. The 
latching element includes an upstanding elongated sheath receiving a 
piston. The upper end of the sheath defines an annular shoulder. A 
latching element-receiving member is firmly affixed to the underside of a 
tilting cab at points overlying the latching elements when the cab is in 
the fully lowered position. The receiving member comprises a cylindrical 
housing having a cap slidably mounted therein for vertical movement 
between first and second positions. A cylindrical keeper is mounted in the 
cap. A plurality of annularly disposed openings in the receiving member 
receive and retain spherical detent elements which are movable radially 
within the openings. The inner diameter of the cylindrical member is only 
slightly larger than the outer diameter of the sheath. 
Additionally, a significant improvement provided by this invention is the 
provision of shock absorber means for absorbing impact created when the 
latching element is pushed into engagement with the receiving member. The 
shock absorber means includes an annular elastomeric member having a 
central opening with inwardly and downwardly tapered side walls. An 
annular bearing plate is affixed to the tapered walls to minimize wear and 
tear on the elastomeric member. However, the absorber eliminates the usual 
undesirable effects of metal-to-metal contact. 
It is a primary objective of this invention to provide a mechanism which is 
relatively simple in structure and is relatively inexpensive to 
manufacture. 
Another objective of the invention is to provide a mechanism of the nature 
wherein an absorber is provided to permit limited movement between the cab 
and the chassis when the vehicle is traversing unusually rough or lumpy 
terrain. 
It is a further objective of this invention to provide a latching mechanism 
which provides for positive locking with a minimum of play between the 
elements which are locked together but, at the same time, permits a 
spring-controlled movement.

Referring now to the drawings wherein like numerals indicate like parts, 
the numeral 10 indicates a chassis of a truck body and the numeral 12 
indicates the lower surface of a tilting cab. Securely affixed and 
extending downwardly from the cab 12 is a cylindrical housing 14. Secured 
to the cylindrical housing 14 is a hat-shaped member 16 having a 
cylindrical portion 18 and an outwardly extending flange 20. 
Circumferentially spaced about the cylindrical portion 18 are a plurality 
of openings 22, each of which receives a ball 24. 
Disposed over the upper end of the hat-shaped member 16 is an inverted 
cup-shaped member 26 formed of a plate 28 and a downwardly depending skirt 
30. An outwardly extending annular ledge 32 of skirt 30 is adapted to 
receive a spring 34 which is disposed between the flange and the lower 
surface of chassis 12. At the lower interior end of skirt 30 there is 
formed an annular chamber 33. When openings 22 are at a level 
corresponding to the chamber 33, the balls 24 can be moved radially 
outwardly into the chamber. 
Disposed interiorly of the cylinder 18 is an annular keeper 40 having an 
interior annular ledge 42 and an exterior annular ledge 44. The ledge 44 
engages a ledge 46 formed on the interior of member 18 when the keeper 40 
is in its lowermost position. A spring 50 is disposed between the 
underside of plate 28 and the ledge 42 to bias the keeper 40 downwardly 
for purposes which will hereinafter be described. 
Disposed below the cylinder 14, the truck bed 10 is formed with an opening 
50. Welded to the bed 10 about the opening 50 is a truncated, generally 
cone-shaped member 52 having an upper opening 54 coaxial with the opening 
50. Welded to member 52 and extending to opening 54 is a sheath 56 having 
a lower end 58 to which a hydraulic fitting 60 is threadably received. 
Interiorly of the upper end of sheath 56 is a cylindrical chamber 62 that 
snugly and slidably receives a piston 64 having an upper operating end 66 
and a lower end 67. At its bottom the sheath 56 has a ring member 68 
welded thereto. Welded to the outer surface at 72 of the ring 68 is an 
upstanding cylindrical cover 70. The upper surface of ring 68 and the 
lower surface of a ring 75, disposed about sheath 56, provide a space for 
a compression spring 77. The ring 75 and the sheath 56 are fixedly secured 
to one another at 74. At its upper end, the sheath has a conical surface 
76. Below the conical camming surface 76 is an annular groove 79 having a 
camming surface 80. 
When the cab 12 is on chassis 10, the cap 26 is biased downwardly against 
the upper surface of flange 20 causing the annular chamber 33 to be below 
the level of openings 22. This forces the balls or detents 24 inwardly 
against the annular camming surface 80 and securely locks the cab 12 to 
the bed 10. 
In order to disconnect the unit, hydraulic pressure is applied through 
fitting 60 causing piston 64 to press against plate 28 driving it upwardly 
toward cab 12. This, in turn, raises the skirt 30 and consequently the 
chamber 33 to a level which permits the detents 24 to move outwardly out 
of engagement with the surface 22. As the cab 12 moves away from the 
chassis member 10, the surface 80 pushes detents 24 into chamber 33. 
When cab and chassis are not connected, the elements assume the positions 
shown in FIG. 2. Note that since the conical portion 76 is no longer 
against the keeper 46, the spring 50 causes the keeper to be biased 
downwardly over openings 22 to maintain the balls 24 in chamber 33. Thus, 
in the event that there is a loss of pressure in chamber 81 and the piston 
64 falls against the supporting rod 82, the cab can still be nested in 
chassis 10 when the cab is lowered. In this instance, the camming surface 
76 will push the keeper 40 upwardly permitting the balls 24 to move 
inwardly beneath the surface 80. 
In the side wall of cylinder 14, a slot 87 is provided to receive a pin 84 
that extends outwardly from skirt 30. The position of pin 84 will indicate 
whether the units are locked together in the presence or absence of 
hydraulic pressure. If the pin 84 is as shown in FIG. 1, it indicates that 
the cap 30 is down and the units are locked together. In the event the pin 
is against the upper end of the slot 87, it indicates the units, although 
nested, are unlocked. 
Although the member 52 is made of a heavy gauge steel, there is some 
flexibility therein. The spring 70, disposed between the rings 68 and 55, 
acts as a shock absorber when forces are transmitted between the cab and 
the chassis; for instance, if the vehicle is traversing difficult terrain. 
A polyurethane annular member 88 secured to the bottom surface of flange 20 
and having an outwardly flared, conical opening 90 covered by a truncated, 
conical wear member 92. The insulator 88 reduces the undesirable effects 
of having metal-to-metal contact between the main locking unit 5 and also 
absorbs some of the shock as the units are brought together. The member 88 
also cooperates to absorb some of the shock transmitted to the cab by 
virtue of a flexure in member 52. 
In FIG. 3 there is shown an embodiment without the shock absorber spring 
77. In such an embodiment, several components can be eliminated such as 
those elements necessary to house spring 77. 
In a general manner, while there has been disclosed an effective and 
efficient embodiment of the invention, it should be well understood that 
the invention is not limited to such an embodiment, as there might be 
changes made in the arrangement, disposition, and form of the parts 
without departing from the principle of the present invention as 
comprehended within the scope of the accompanying claims.