Torque limiting cap for air conditioning service ports

A torque-limiting cap (100) for an air conditioning service port (14) includes an inner body assembly (122) having a retaining body (116) configured for engagement on the service port, and an outer body assembly (134) annularly disposed around the inner body assembly. The outer body assembly (134) has a first ratchet portion (140) configured for engagement with a second ratchet portion (146) that is disposed on the inner body assembly (122). When the outer body assembly (134) is torqued, the outer body assembly transmits the torque to the inner body assembly (122) from the first ratchet portion (140) to the second ratchet portion (146) to threadably engage the retaining body (116) onto the service port (14). When there is a preset amount of torque resistance, the first ratchet portion (140) slips with respect to the second ratchet portion (146) such that no additional torque is transmitted to the inner body assembly (122) from the outer body assembly (134).

FIELD OF THE INVENTION

The present invention relates generally to a cap for service ports, and more particularly, to a cap for air conditioning service ports.

BACKGROUND OF THE INVENTION

Typically, air conditioning service ports have a cap to prevent the loss of refrigerant from the air conditioning system. The service port of the air conditioning system typically includes a tube that is threaded on an interior surface of the tube. Conventionally, the cap has an inner body that is received around the periphery of the service port, and a threaded retaining body that is received on the interior surface of the service port. An upper sealing surface spans across the retaining body and the inner body of the cap.

When the cap is engaged on the service port, the tube of the service port is received between the retaining body and the inner body of the cap. The engagement of the threaded interior surface of the service port and the threaded retaining body, in combination with the engagement of the upper sealing surface and/or the inner body with the exterior surfaces of the service port, form a seal to prevent the loss of refrigerant.

However, when the cap is installed on the service port, it is typically installed by hand. Since there is no mechanism for the technician to provide consistent torque to each cap installed, the caps may not be properly installed on a consistent basis. Improperly tightened air conditioning caps onto service ports can result in a loss of refrigerant from the air conditioning system. This leaking of refrigerant can have a negative impact on the environment and can reduce the performance of the air conditioning system.

SUMMARY OF THE INVENTION

A torque-limiting cap for an air conditioning service port includes an inner body assembly having a retaining body configured for engagement on the service port, and an outer body assembly annularly disposed around the inner body assembly. The outer body assembly has a first ratchet portion configured for engagement with a second ratchet portion that is disposed on the inner body assembly. When the outer body assembly is torqued, the outer body assembly transmits the torque to the inner body assembly from the first ratchet portion to the second ratchet portion to threadably engage the retaining body onto the service port. When there is a preset amount of torque resistance, the first ratchet portion slips with respect to the second ratchet portion such that no additional torque is transmitted to the inner body assembly from the outer body assembly.

DESCRIPTION OF A PREFERRED EMBODIMENT

Referring toFIG. 1, a prior art air conditioning cap is indicated generally at10, and includes an inner body12that is configured to be received around the periphery of a service port14, and a threaded retaining body16that is received on an interior surface18of the service port. An upper sealing surface20spans across the retaining body16and the inner body12of the cap10. When caps10are installed by a technician onto service ports14, an inconsistent amount of torque can be applied to each cap by the technician. For this reason, the caps10may not be properly and consistently installed on the service port14. Improperly tightened caps10on the air conditioning service ports14can result in a loss of refrigerant from the air conditioning system.

Referring now toFIG. 2, a cap in accordance with the invention is indicated generally at100. The cap100is configured to be received on a conventional service port14, and includes an inner body112that is configured to be received around the periphery of the service port14, and a threaded retaining body116that is received on the threaded interior surface18of the service port. An upper sealing surface120spans across the retaining body116and the inner body112of the cap100.

Together, the threaded retaining body116, the inner body112and the upper sealing surface120form the inner body assembly122. The inner body112includes a first portion124adjacent the upper sealing surface120that has a first diameter, and a second portion126at the distal end of the inner body having a second diameter larger than the first diameter. At the first portion124, a pocket128is disposed for receiving a radial O-ring seal130, which seals the peripheral surface of the service port14with the inner body112. Between the first portion124and the second portion126is a shoulder132that receives a locator projection22on the service port14having a generally corresponding size. When the cap100is engaged on the service port14, the locator projection22engages the shoulder132.

An outer body assembly134is generally concentrically disposed around the inner body assembly122. The outer body assembly134includes an outer body136, a top surface138and a first ratchet portion140, where the outer body and the first ratchet portion are generally normal to the top surface. The top surface138forms a secondary sealing surface to keep moisture and debris out of the cap100. The top surface138is generally parallel with the sealing surface120, and the outer body136is generally concentric with the retaining body116.

Disposed between the outer body136and the inner body112is the first ratchet portion140. The first ratchet portion140includes an annular extension142that extends generally normally from the top surface, and a pawl144that extends generally radially inward from the extension. The pawl144of the first ratchet portion140is configured to engage a second ratchet portion146on the inner body112.

Formed at a peripheral surface of the inner body112, the second ratchet portion146is a receiving pocket148configured to receive the pawl144. As seen inFIG. 3, the receiving pocket148has a radial surface150and an angled surface152that generally corresponds with a radial side154and an angled side156of the pawl144, respectively. The angle of the angled surface152and the angled side156has a component that is parallel to the tangential of the “tighten” direction.

When the technician installs the cap100onto the service port14, the cap is torqued and the threads on the retaining body116cooperate with the threads on the interior surface of the service port. As the cap100is initially torqued onto service port14, the inner body assembly122and the outer body assembly134have a generally static relationship to each other. When the technician torques the outer body assembly134, the torque is transmitted to the inner body assembly122through the engagement of the pawl144in the receiving pocket148. When the cap100is torqued to the extent that the locator projection22is engaged on the shoulder132, or when the service port14is engaged with the sealing surface120, or at any other present amount of torque resistance caused by the engagement of the cap onto the service port, the cap limits the torque applied to the inner body assembly122.

The torque is limited by the cap100with the first ratchet portion140and the second ratchet portion146, which together form a ratchet assembly158. Due to the geometry of the pawl144and the receiving pocket148, when the outer body assembly134is torqued, the first ratchet portion140slides out of the receiving pocket along the angled side156and the angled surface152, respectively, and there is an interference between the first ratchet portion and the second ratchet portion146. The first ratchet portion140deflects to clear the inner body112.

A ratchet spring160is annularly disposed between the first ratchet portion140and the outer body136to reinforce the first ratchet portion. When the first ratchet portion140and the second ratchet portion146are in an interference, the outer body136and the first ratchet portion are deflected radially outward. The ratchet spring160provides the primary resistance to the radial outward deflection of the first ratchet portion140.

As the technician torques the outer body assembly134and the first ratchet portion140slides past the second ratchet portion146, torque is not transmitted to the inner body assembly122. In this way, if the technician continues to torque the cap100, the torque is not transmitted to the inner body assembly122, but is instead limited to the outer body assembly134.

When the technician uncaps the service port14, the technician torques the cap100in the opposition direction. As seen inFIG. 3, when the first ratchet portion140is torqued in the “loosen” direction, torque is transmitted by the radial side154of the pawl144to the radial surface150of the receiving pocket148of the second ratchet portion146. Since the radial side154and the radial surface150do not have a component parallel to the tangential of the “loosen” direction, the first ratchet portion140and the second ratchet portion146are prevented from slipping past each other in the “loosening” direction, and the torque applied from the outer body assembly134will be transmitted to the inner body assembly122.

A snap ring162is annularly disposed in a groove164at the distal end of the inner body112and the outer body136. The snap ring162maintains the inner body assembly122and the outer body assembly134together to form the cap100, and also maintains the ratchet spring160between the inner body112and the outer body136.

It is contemplated that any number of ratchet assemblies158can be annularly disposed on the cap100. Further, it is contemplated that the pawl144and the receiving pocket146can have other shapes and sizes that permit slipping in one torqueing direction, and that prevent slipping in the other torquing direction. Advantageously, the inner body assembly122and the outer body assembly134are both formed of plastic, however other non-rigid materials are contemplated. It is also contemplated that the inner body assembly122can include the pawl144, and that the outer body assembly134can include the receiving pocket148.

The cap100provides a torque-limiting feature that enables the technician to install each cap on each service cap14in a consistent manner, while also ensuring that the cap forms a proper seal to prevent refrigerant loss. The cap100obviates the need for the technician to use a torque wrench, which is inconvenient to use. By installing the cap100, the time and costs associated with assembling the air condition system are reduced.