1. Technical Field of the Disclosure
The present embodiment is related in general to chucks for use in connection with pumps for inflating bicycle tires or other inflatable objects, and in particular to a pump chuck that uses air pressure from the tire pump to push a seal against the valve stem of a tire valve to produce an air tight seal.
2. Description of the Related Art
It is well known that for inflating the tires of vehicles, particularly two-wheel vehicles such as bicycles, motorcycles, or motor-assisted cycles, a flexible connector is generally used having one end coupled and sealed to a source of air under pressure such as a bicycle pump or hand air pump, the other end is sealed onto the valve stem of the tire valve. Tire inflation devices typically have a chuck for attaching to and substantially sealing at the valve stem of the tire valve (or other inflatable article). In order to properly inflate the article, the chuck must seal at the valve and limit or preclude leakage of air at the chuck-valve connection. Often, such a seal is not readily made with conventional chucks and leakage occurs, often leading to improperly inflated tires or articles.
Conventional chucks on bicycle tire pumps are difficult to use as they use a cam and lever to compress a rubber seal against the valve stem. The rubber seal must prevent air leaks at pressures up to 125 PSI as well as retain the chuck on the stem at pressures up to 125 PSI. This requires a significant lever force to compress the rubber seal making it hard to attach the chuck to the valve stem. Further, it is difficult to insert the chuck on to the valve stem due to tight seal clearance and it is difficult to actuate the cam lever due to the large force required to compress the seal on to the valve stem. Moreover, it is also difficult to hold the stem tightly to insert the chuck on to the valve stem when tire is flat or has little air.
Recent advancements in the art disclose a chuck for connecting a pressure device to a valve stem of a pressurized vessel including a body portion having a first passageway that is configured to receive an outer tube portion of a valve stem of a pressurized vessel therein. The body portion has a guide portion at an inner end of the first passageway. A pin element is movably disposed within a second passageway of the body portion and is movable along the coaxial passageways. The guide portion includes an alignment element at least partially around the second passageway and extending longitudinally toward an engaging end of the body portion and at least partially around the pin element for engaging and supporting an interior portion of the end of the outer tube portion of the valve stem. However, external pressure has to be applied to form an air tight seal.
One of the existing pump chucks comprises a main body defining a chamber and having a top end and a bottom end; a force transmitting member positioned in the chamber adjacent to the top end of the main body; a resilient collar positioned in the chamber adjacent to the bottom end of the main body and in engagement with the force transmitting member; and a camming device mounted at the top end of the main body. The collar defines an axial cavity having an inner wall and an inside diameter. Compression of the collar decreases the inner diameter of the collar, and thus causes the collar to engage and seal the valve stem positioned in the axial cavity. However, the user will have to exert significant force to compress the collar to engage and seal the valve stem.
Another existing device discloses an air chuck that provides a manual press-fitted connection to the valve stem of an automobile tire or the like, consisting of a tubular body member attachable to the hose end and having a pressure-seated plunger valve therein. The plunger valve has a plunger extension which, when pressed over the valve stem of an automobile tire, opens both the plunger valve and the air valve of the stem to admit air to the stem. The invention is characterized by the construction of the body member, hose and plunger valve assembly, wherein a single assembly member performs the functions of providing a sealed connection of the hose to the body member, limiting and controlling the motion of the plunger valve, and providing for air passage from the hose to the plunger valve. However, the connection has to be made manually by pressing the plunger.
Various other pump chucks exist that are used in tire inflating devices. One such device includes an air chuck for tire valves having a plurality of teeth which positively lock the chuck to the valve stem by a plurality of closely spaced, radially inwardly projecting fingers which are moved into engagement with the valve stem by sliding a sleeve member over the fingers. The chuck includes a means for depressing the tire valve pin and a means for sealing the outer end of the valve when the chuck is engaged. Another device includes a quick-coupling connector that comprises a tubular body with a piston actuator which may be formed in one or two parts between an operating lever and a sealing ring which in response to the displacement is compressed and tightly squeezed against the inflation valve conforming to its threaded outer surface and forming an air-tight connection. However, such devices require significant lever force to compress the rubber around the valve stem.
Based on the foregoing there is a demonstrable need for a pump chuck that easily attaches to the valve stem of a tire valve. Such a needed pump chuck would use a pneumatic piston and air pressure from the tire pump to form a seal against the valve stem enabling an air tight seal. The pump chuck would comprise a pivot clip that secures the valve stem in the pump chuck. Further, the pump chuck would be easy to hold over the valve stem when the tire is flat. The pump chuck would also comprise an optional adjustable pressure relief valve to set the desired pressure. Finally, the fastening device would be economical, reliable and easy to use. The present invention overcomes prior art shortcomings by accomplishing these critical objectives.
To minimize the limitations found in the prior art, and to minimize other limitations that will be apparent upon the reading of the specifications, the preferred embodiment of the present invention provides a pump chuck that uses air pressure from the tire pump to push a seal against the valve stem of a tire valve to affect an air tight seal.
The present invention discloses a pump chuck that easily attaches to the valve stem. The pump chuck automatically forms an air tight seal with the first stroke of the tire pump.
The preferred embodiment of the pump chuck comprises a body, a pivot clip, and a pneumatic piston. The body has a first bore to receive the pneumatic piston and a rubber flat washer and a second bore to receive a compression spring. The body has a third bore to receive the connector for the hose from the tire pump. The pivot clip is pivotally mounted on the body by means of a pivot screw. The pivot clip compresses the compression spring against the body. The pump chuck further comprises an end cap mounted on the body above the first bore that houses the piston and the washer. The end cap has a smooth bore just slightly bigger than the valve stem diameter. The pivot clip has a plurality of threads that match the threads on the valve stem to secure the stem to the chuck. The bottom side of the end cap retains the rubber washer in the first bore with the piston.
For the purpose of attaching the pump chuck to the valve stem, the pivot clip is pushed down and the valve stem is inserted into the bore in the end cap. The pivot clip must move far enough so the threads in the pivot clip clear the valve stem. The pivot clip is then released causing the compression spring to push the pivot clip against the valve stem thereby holding the valve stem tightly between the pivot clip and the end cap. When the tire pump increases the air pressure, the valve stem is pushed in the top direction by the pneumatic piston. The pivot point is located close to the outside diameter of the valve stem to hold the stem in place as the piston pushes against the stem. The pressure holding the seal against the stem increases as the tire pressure increases.
The pump chuck may further comprise an optional adjustable pressure relief valve. The adjustable pressure relief valve does not let the pump exceed pre-set pressure thereby eliminating the need for a pressure gauge on the tire pump. The adjustable pressure relief valve has an adjustment knob which can be turned to set desired pressure.
The present invention easily slips over the valve stem and the pivot clip opens like a clothes pin to secure the pump chuck to valve stem. It is easy to hold the valve stem when inserting the pump chuck when the tire is flat because the pump chuck easily attaches to the valve stem. Further, the pump chuck may be used with two types of valve stems—Schrader Valve and Presta Valve.
A first objective of the present invention is to provide a pump chuck that is easily attaches to the valve stem.
A second objective of the present invention is to provide a pump chuck that requires no external pressure to form an air tight attachment to the valve stem.
A third objective of the present invention is to provide a pump chuck that automatically forms an air tight seal with the first stroke of the tire pump.
Another objective of the present invention is to provide a pump chuck that is compatible with Schrader Valve and Presta Valve.
A further objective of the present invention is to provide a pump chuck that is easy to use, economical and reliable.
These and other advantages and features of the present invention are described with specificity so as to make the present invention understandable to one of ordinary skill in the art.
Elements in the figures have not necessarily been drawn to scale in order to enhance their clarity and improve understanding of these various elements and embodiments of the invention. Furthermore, elements that are known to be common and well understood to those in the industry are not depicted in order to provide a clear view of the various embodiments of the invention, thus the drawings are generalized in form in the interest of clarity and conciseness.
In the following discussion that addresses a number of embodiments and applications of the present invention, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. It is to be understood that other embodiments may be utilized and changes may be made without departing from the scope of the present invention.
Various inventive features are described below that can each be used independently of one another or in combination with other features. However, any single inventive feature may not address any of the problems discussed above or only address one of the problems discussed above. Further, one or more of the problems discussed above may not be fully addressed by any of the features described below.
For attaching the pump chuck 10 to the valve stem 22, the pivot clip 14 is pushed down and the valve stem 22 is inserted into the bore 54 in the end cap 18. The pivot clip 14 must be moved far enough so that the plurality of threads 48 in the pivot clip 14 clear the valve stem 22. The pivot clip 14 is then released causing the compression spring 16 to push the pivot clip 14 against the valve stem 22 thereby holding the valve stem 22 tightly between the pivot clip 14 and the end cap 18. When the tire pump (not shown) increases the air pressure, the valve stem 22 is pushed in the upward direction by the pneumatic piston 24. The pivot point 60 is located close to the outside diameter of the valve stem 22 (See
The pump chuck 10 is compatible with two types of valve stems—Schrader Valve and Presta Valve. The various components of the pump chuck 10 change slightly in dimensions for the two types of valve stems. The pivot clip 14 has M8 X.75P threads for Schrader Valve and M6 X.75P threads for Presta Valve. The end cap 18 has a bore 54 with 7.8 mm diameter for Schrader Valve and a bore 54 with 6.1 mm diameter for Presta Valve. The distance between the central axis of the valve stem 22 and the pivot point 60 (See
The presently disclosed pump chuck 10 is advantageous because it provides it easily slips over the valve stem 22 and the pivot clip 14 opens like a clothes pin to secure the pump chuck 10 to the valve stem 22. There is no need to apply external pressure to the pump chuck 10 in order to produce an air tight seal. Further, it is easy to hold the valve stem 22 when inserting the pump chuck 10 when the tire is flat because the pump chuck 10 may be easily engaged with the valve stem 22. Further, the pump chuck 10 is compatible to use with both Schrader Valve and Presta Valve.
The foregoing description of the preferred embodiment of the present invention has been presented for the purpose of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of the above teachings. It is intended that the scope of the present invention not be limited by this detailed description, but by the claims and the equivalents to the claims appended hereto.