The present invention relates to a coupling half for a quick-connect coupling such as a hose coupling.
The advantages, especially for fire-fighting where time is very important, of being able quickly to connect together water carrying members has long been known and there are several designs for couplings that, with one quarter turn, or less, of two interacting coupling halves, create a watertight seal between two water carrying members such as hoses, valves, nozzles etc. Such couplings may be said to fall within one of two categories: 1) "male and female"; 2) "identical", sometimes called "sexless", couplings. Identical couplings have the advantage that any coupled end of any water carrying member may be presented for connection to any other of the same type. The present invention relates to a coupling of the identical type.
There is on the market an identical coupling sold under the name Storz, in which the coupling halves each have a cam ring which is rotatable relative to the associated hose connection piece and whose cams engage in a bayonet-type locking engagement with grooves of the cam ring of the other respective coupling half. The grooves, which are annular in form, have a slope and the turning of the cam rings causes the hose connection halves to draw together axially. An example of such coupling is seen in U.S. Pat. No. 4,524,997 issued to Ebert Jun. 25, 1985. Although this general type of coupling has received wide usage it poses certain disadvantages in operation, particularly the problem inherent in all quick connect couplings--that of potential unintentional de-coupling. De-coupling forces may arise as a result of water-pressure induced torque or as a result of the manouvering of hose or other fire-fighting equipment. With the Storz coupling, the cam rings are built such that when rotationally engaging the two coupling halves maximum compression of the mating seals upon the face of each coupling half is achieved when the coupling is rotated through the first part of its rotational range. Thereafter, as rotation is continued to its limit, because the grooves of the engaging cam rings are then reverse sloped, the coupling halves will move slightly away from each other axially and allow the seals to de-compress partially. The coupling will then resist de-coupling by making it necessary to both compress the seals and to rotate them in opposite directions against their compressed contact before de-coupling can take place. The disadvantage of this type of coupling is that it is difficult to rotationally engage or disengage the coupling halves and, of course, the larger the diameter of the coupling the more the force which is required to engage or disengage it. This design also has the disadvantage that because all the interlocking features are located on the face of the coupling they become hidden from view once the coupling halves are engaged and initially rotated, thus there is no visual reference to indicate whether or not any two engaged coupling halves are fully rotated or not.
A second type of coupling is marketed by the National Fire Hose Corporation of Compton, Calif. (J.M. Huber, manufacturer) under the proprietary name STAYTITE, as seen in the U.S. Pat. No. 4,643,459. These couplings connect with less than a quarter turn and, when fully rotated are automatically locked against rotation by the engagement of a six piece spring-assisted locking plug and locking slide assembly located in each coupling half. This design suffers from practical disadvantages; it is expensive to produce, there is a likelihood of part failure, and it is difficult to repair.
U.S. Pat. No. 1,112,850, issued on Oct. 6, 1914 to Sherer, shows a hose coupling which has sexless members with circumferentially slotted hooks for interlocking engagement with corresponding studs. Locking pins are also provided with this device to prevent the studs from being withdrawn from their corresponding hooks. The locking pins are normally urged to a protruding position by abutment against the edge of a rotatable collar of the coupling. The rotatable collar provides a series of notches which effect retraction of the locking member. This device uses a threaded and unbiased collar for the couplings, an arrangement which proves to be relatively cumbersome to operate under field conditions.
U.S. Pat. No. 4,643,459 issued on Feb. 17, 1987 to Carson, discloses a coupling half with locking pins which are biased to extend outwardly of the coupling faces, and are retracted during coupling by a ramped end of the sidewall extensions. Further rotation of the coupling members then causes each coupling pin to fall into its corresponding receptacle. To unlock the coupling cammed circumferential slides are activated to retract the pins out of the receptacles. This arrangement proves to be difficult to operate since the locking pins of each half are not maintained in an extended position ready for rapid reattachment and locking of the halves after disconnection. Furthermore, to disconnect the coupling halves the operator must retract the locking pins in a first movement, and then in a second movement proceed to uncouple the two halves of the hose coupling by relative rotation of the one to the other, making rapid disconnection difficult.
It is an object of the present invention to provide an improved lock system for a quick-connect coupling. This invention is particularly directed towards the sealable engagement of conduit members which carry pressurized water and more particularly again towards engagement of conduit members of a large diameter which are difficult to maneuver and lock. No special knowledge of coupling hoses is required to use the coupling halves of the present invention. This can be particularly advantageous in field conditions where untrained volunteer fire-fighters may be used.