Patent Application
20060243019
The present invention relates generally to tube flaring. More particularly, the present invention relates to pneumatic-hydraulic tube end flaring tools.
Tubing of various types and sizes is used in myriad applications to transport fluids, for example, from one component of a machine to another component. The transported fluid may be under pressure, either low pressure or high pressure. For example, in automobiles and other vehicles, fuel may be transported from a reservoir to the engine, and hydraulic brake fluid commonly is transported from a main hydraulic cylinder to the individual braking cylinders on the vehicle wheels by way of tubing. The tubing may be any cylindrical conduit, however, malleable metal tubing is commonly used in many applications.
A variety of conventional fittings, adapters and couplers have been used for connecting malleable cylindrical metal conduits, or tubing, to other tubing or to fixtures, many of which require that the tube end be formed into a flared end to seal against the fittings, adapters or couplers. An assortment of tube flaring tools have been developed to plastically deform the malleable metal tube end. For example, some tube flaring tools insert a conical member into the end of the tube while a tooling die is placed around the outer portion of the tube end, and the flared tube end is formed between the conical member and the tooling die by plastic deformation of the metal tubing.
In addition, a number of common standards have been developed for specific types and shapes of flared tube ends. For example, the Society of Automotive Engineers (SAE) has published standards for flared tube ends, as has the International Organization for Standardization (ISO). Thus, the shape of the flared tube end is contoured accurately to conform to the seating surface of a standard conventional fitting, adapter or coupler to which the tubing is to be connected.
Existing tube flaring tools require manual force, such as through a leveraged screw-type tool, an impact-type tool requiring the use of a hammer, or a manual pump hydraulic hand tool. Accordingly, it is desirable to provide a method and apparatus that forms a flared end on malleable metal tubing that does not require significant manual force for operation.
The foregoing needs are met, to a great extent, by the present invention, wherein in one aspect a method and apparatus are provided that in some embodiments provide a tube flaring tool for forming a flared end on malleable metal tubing that is actuated by a two-stage pneumatic-hydraulic actuator.
In accordance with one aspect of the present invention, a tube flaring device includes a pneumatic actuator and a hydraulic actuator operatively connected to the pneumatic actuator. The tube flaring device also includes a ram mechanically coupled to the hydraulic actuator. A distal end of the ram includes an interior portion of a shape to form a flared tube end. The tube flaring device further includes a plurality of die elements, a proximal aggregate end of which includes an exterior portion of the shape to form the flared tube end. The pneumatic actuator actuates the hydraulic actuator, which in turn actuates the ram to form the flared tube end.
In accordance with another aspect of the present invention, a method of forming a flared tube end includes the step of clamping a tube having a tube end between a plurality of die elements that include an aggregate interior surface defining a central bore to hold the tube in place, the plurality of die elements including a proximal aggregate end including an exterior portion of a shape to form a flared tube end. The method also includes the steps of channeling a compressed gas into a cavity on a pressure side of a pneumatic piston to actuate the pneumatic piston and actuating a plunger to apply a force to a hydraulic fluid in a cylindrical bore on a pressure side of a hydraulic piston to actuate the hydraulic piston. The method further includes the step of actuating a ram to impinge the tube end, a distal end of the ram including an interior portion of the shape to form the flared tube end.
In accordance with yet another aspect of the present invention, a tube flaring device includes means for clamping a tube having a tube end between a plurality of die elements that include an aggregate interior surface defining a central bore to hold the tube in place. The plurality of die elements includes a proximal aggregate end including an exterior portion of a shape to form a flared tube end. The tube flaring device also includes means for channeling a compressed gas into a cavity on a pressure side of a pneumatic piston to actuate the pneumatic piston and means for actuating a plunger to apply a force to a hydraulic fluid in a cylindrical bore on a pressure side of a hydraulic piston to actuate the hydraulic piston. The tube flaring device further includes means for actuating a ram to impinge the tube end and form a flared tube end. In this aspect, a distal end of the ram includes an interior portion of the shape to form the flared tube end.
There has thus been outlined, rather broadly, certain embodiments of the invention in order that the detailed description thereof herein may be better understood, and in order that the present contribution to the art may be better appreciated. There are, of course, additional embodiments of the invention that will be described below and which will form the subject matter of the claims appended hereto.
In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of embodiments in addition to those described and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein, as well as the abstract, are for the purpose of description and should not be regarded as limiting.
As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.
An embodiment in accordance with the present invention provides an air-driven hydraulic (also pneumatic-hydraulic, pneu/hydraulic, or air over hydraulic) tube flaring tool, including an actuator assembly and a tool head assembly. The actuator assembly includes an actuation trigger lever, a slide valve, a pneumatic actuator and a hydraulic actuator. The tool head assembly attaches to the actuator assembly and includes a tube flaring ram and a matching two-piece die set for forming a flared end on a malleable metal tube. This embodiment of the invention has the advantage that less physical force or effort and less time are required to form a flared tubing end on a malleable metal tube.
The invention will now be described with reference to the drawing figures in which like reference numerals refer to like parts throughout. An embodiment of the present inventive apparatus and method is illustrated in
Compressed air from an external source enters into the pneumatic actuator cavity 18 through an orifice 34, creating a force on the pressure side of the pneumatic piston 22 which urges the pneumatic piston 22 toward the distal end of the pneumatic actuator cavity 18 (in the left-hand direction in
The cylindrical bore 38 opens into the hydraulic actuator cavity 20. A hydraulic piston 46 seals against the walls of the hydraulic actuator cavity 20 with the aid of an O-ring 48 and a back-up ring 50, which has an interference fit with the walls of the hydraulic actuator cavity 20, to help prevent the O-ring 48 from becoming entrapped between the hydraulic piston 46 and the walls of the hydraulic actuator cavity 20. Thus, as the plunger 36 moves in the direction of the hydraulic actuator cavity 20, hydraulic fluid 40 is displaced into the hydraulic actuator cavity 20 on the pressure side of the hydraulic piston 46, forcing the hydraulic piston 46 to move in a direction away from the proximal end of the hydraulic actuator cavity 20.
The ratio of the area of the pressure side of the pneumatic piston 22 to the area of the distal end of the plunger 36 creates a pressure multiplier, and the area of the pressure side of the hydraulic piston 46 to the area of the distal end of the plunger 36 creates a force multiplier. For example, in one embodiment of the invention, the ratio of the area of the pressure side of the pneumatic piston 22 to the area of the distal end of the plunger 36 is approximately 33:1, and the ratio of the area of the pressure side of the hydraulic piston 46 to the area of the distal end of the plunger 36 is approximately 7.84:1. In this embodiment, the nominal air pressure introduced into the pneumatic actuator cavity 18 on the pressure side of the pneumatic piston 22 is approximately 90 pounds per square inch gauge pressure (psig).
A resilient element 52 applies a bias force against the backside of the hydraulic piston 46 tending to maintain the hydraulic piston 46 toward the proximal end of the hydraulic actuator cavity 20. The distal end of the resilient element 52, preferably a helical spring as shown in the embodiment in
The actuator assembly 12 also includes a handle portion 60 with a generally cylindrical valve cavity 62. A substantially cylindrical slide valve 64 seals against the walls of the valve cavity 62 with the aide of two O-rings 66, 68. The slide valve 64 protrudes from an open end of the valve cavity 62 and a trigger lever 76 is pivotally attached to the actuator housing 16 in order to contact the protruding end of the slide valve 64 to depress the slide valve 64, moving the slide valve 64 toward a closed end of the valve cavity 62. A resilient element 78 applies a bias force against the slide valve 64 in a direction toward the open end of the valve cavity 62. For example, in the embodiment shown in
An inlet channel 70 in the handle portion 60 of the actuator housing 16 leads from a threaded inlet bore 72, which is configured for attachment of an external pneumatic fitting for connecting to an external source of compressed air to the actuator housing 16, and opens into the valve cavity 62 at a location relatively near the closed end of the valve cavity 62. A supply channel 74 leads from the valve cavity 62 to the orifice 34, opening into the pneumatic actuator cavity 18 on the pressure side of the pneumatic piston 22. In addition, an exhaust channel 75 leads from the valve cavity 62 to the exterior of the actuator housing 16.
The two O-rings 66, 68 are oriented on the slide valve 64 such that the inlet channel 70 and the supply channel 74 are in fluid communication when the slide valve 64 is at a position toward the closed end of the valve cavity 62. When the slide valve 64 is at a position toward the open end of the valve cavity 62, the inlet channel 70 and the supply channel 74 are not in fluid communication, but the exhaust channel 75 is in fluid communication with the supply channel 74. Thus, compressed air entering through the threaded inlet bore 72 can be selectively introduced into the pneumatic actuator cavity 18 on the pressure side of the pneumatic piston 22 by depressing the slide valve in order to actuate the pneumatic piston 22 toward the distal end of the pneumatic actuator cavity 18. When the pneumatic piston 22 and the attached plunger 36 are actuated, the hydraulic piston 46 is in turn actuated and the appendage 58 extends in the direction of the tool head assembly 14. When the slide valve 64 is released, compressed air is vented from the pressure side of the pneumatic piston 22 through the supply channel 74 and out to the atmosphere by way of the exhaust channel 75.
A perspective view of the tool head assembly 14 is shown in
In operation, a tube 98 is introduced through an opening 100 in the distal end of the casing 80 into a cylindrical bore in the middle of the two die elements 86, 88, which has an interference fit with the exterior of the tube 98, in order to grip the tube 98 and hold it in place. In this embodiment of the invention, the tube 98 is placed between the two die elements 86, 88 before the die elements 86, 88 are placed into the casing 80, such that the tube end is flush with the proximal end of the die elements 86, 88. Then, the die elements 86, 88 and the tube 98 are placed into the casing 80 and clamped in place by the clamping screw 92.
As shown in
In various preferred embodiments of the invention, the distal end of the ram 84 and the proximal ends of the die elements 86, 88 may be configured in different shapes to form variously shaped flared tube ends 102. In individual embodiments of the invention, the geometrical shape of the ram 84 and of the die elements 86, 88 corresponds to a suitable standard configuration for flared tube ends 102. For example, in an embodiment of the invention, the distal end of the ram 84 is formed in a conical shape, forming edges at a 45° angle with the axis of the ram 84 and the axis of the tube 98. In another embodiment of the invention, the ram 84 and the die elements 86, 88 are configured to correspond to a 45° double-flared tube end per the Society of Automotive Engineers (SAE) J533 standard, which is hereby incorporated by reference in its entirety. In yet another embodiment of the invention, the ram 84 and the die elements 86, 88 are configured in accordance with the 37° single-flared tube end per the SAE J533 standard. In other embodiments of the invention, the ram 84 and the die elements 86, 88 may be configured in accordance with any other standard or specification, for example, a “bubble” flared tube end per the International Organization for Standardization (ISO) 4038 standard, which is hereby incorporated by reference in its entirety; a “push-connect” type flared tube end per the SAE J2044 standard, which is hereby incorporated by reference in its entirety; a General Motors (GM) fuel tube flared end per a General Motors Corporation proprietary specification; or any other flared tube end configuration standard, convention or specification as determined by a standards organization, a private company, or the like.
Although an example of the tube flaring tool is shown in
Similarly, although an example of the tube flaring tool is shown in
Likewise, although an example of the tube flaring tool is shown in
The many features and advantages of the invention are apparent from the detailed specification, and thus, it is intended by the appended claims to cover all such features and advantages of the invention which fall within the true spirit and scope of the invention. Further, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.
