Patent Application
20060277968
1. Field of the Invention
This invention relates to tubing benders and more particularly to tubing benders capable of effecting bends in tubing of differing diameters. Specifically, it relates to improved tubing benders with improved tubing retention and handling properties.
2. Description of the Prior Art
Electricians have used portable tubing benders to bend electrical conduit. Similarly plumbers and other craftsmen have used tubing benders to bend tubing for a variety of applications. A typical tubing bender includes a mandrel having an arcuate groove or recess. The radius of the arc of the groove roughly corresponds with the radius of bend, or bending radius, to be imposed upon the tubing. The groove is typically semicircular in cross section with a radius that generally corresponds to the outside radius of the tubing, the holding radius. The mandrel is secured to a handle while a forming press having complementary surfaces is secured to a second handle and the handles are pivotally connected together. A hook arrangement, or tube retainer, is provided to retain the tubing in appropriate orientation with the groove in the mandrel as bending is effected by relatively rotating the handles such that the forming press orbits around the mandrel groove. There have been tubing benders having mandrels with sets of arcuate grooves, or tube recesses, which have different arc radii. This allows such a tubing bender to be prepared to bend tubes to different radii without assembling a new mandrel to the remainder of the bender. An example of the foregoing can be found in U.S. Pat. No. 6,487,889, which is fully incorporated herein by this reference.
While tubing benders of this type increase the flexibility for bending tubing to different radii, they still have substantial shortcomings. They are awkward to handle both while providing the necessary bending moments and during installation of tubing to be bent. While providing the bending moments, the operator frequently feels as though another hand is needed. With one hand on each handle and the tubing placed in the bender, the entire assembly becomes unwieldy when the operator must support the bender with a length of tubing inserted therein and at the same bring the handles together to accomplish a bend with an arc of adequate precision to make the bent tube useful. Even more significant, the placement of the tube to be bent into the bender requires holding the tube in place while holding the bender, with its tendency to bend uncontrollably about the mandrel, while concurrently coping with tricky placement of the hook arrangement about the tube and, with all hands already occupied, tightening a thumbscrew to hold the hook in place that is to hold the tube in place. This clearly is job for which a juggler may be best suited.
Thus, it highly is desirable to provide a tool for bending tubing to a range of bend radii and over a range of arcs that is less clumsy both during insertion of tubing to be bent and during actual bending of the tube, allowing a quicker and more precise bending process.
Accordingly, even though portable tubing benders have been in use for a long time, there is a continuing need for such a tubing bender.
The present invention has as an object the provision of a tubing bender with greater ease of use.
The present invention is an improved tubing bender of the type having a mounting base, a mandrel mounted upon the mounting base and having a tube recess, and a tube retainer mounted upon the mounting base. It is improved by the tube retainer being mounted upon the mounting base by a snap-lock journal.
The accompanying drawings, which are incorporated in and form part of the specification in which like numerals designate like parts, illustrate preferred embodiments of the present invention and together with the description, serve to explain the principles of the invention. In the drawings:
Referring to
Tube retainer 38 includes retaining portion 46 comprising mandrel side 40, having compliments to grooves 30 in the form of steps 42 upon ramp 44, press fit hole 43, retainer abutment 45, open stop wall 47, and pivotal face 51 (depicted in
The combination of stop abutment 26 and retainer abutment 45 cooperate to form a pivot stop. The combination of stop abutment 26, retainer abutment 45, pivot hole 18, compression spring 50, rotation pin 48 and button 49 form a snap-lock journal for tube retainer 38, in relation to mounting base 12. A snap-lock journal being a pivotal connection where the pivoting item can move about its pivot point, over a portion of its available range of motion, but has a point where a spring bias causes a discontinuous restriction on the available range of motion.
When tube retainer 38 is in the position depicted in
When button 49 is depressed, tube retainer 38 lifts from close face 24. If button 49 is depressed enough, retainer 38 will sit higher than open face 22. In this condition, tube retainer 38 can be rotated clockwise about the pivot formed by pivot hole 18 and rotation pin 48 until open stop wall 47 contacts upper recess wall 20. Releasing button 49, at this point, allows the bias from compression spring 50 to pull tube retainer 38 to a resting position in upper recess 23 and against open face 22. Tube retainer 38 can be rotated counterclockwise sliding pivotal face 51 across open face 22 without depressing button 49. When retainer abutment 45 aligns with stop abutment 26, the bias provided by compression spring 50 causes tube retainer 38 to drop or snap into lower recess 21. Anytime prior to alignment of retainer abutment 45 with stop abutment 26, tube retainer 38 can be slid clockwise to the point that retainer abutment 45 is proximate to upper recess wall 20. Once tube retainer 38 drops into lower recess 21 it cannot be returned to upper recess 23 without dressing button 49.
Link 52 is pivotally mounted upon mandrel 28 with first link bolt 58. First link bolt 58 is inserted through first link hole 54 and then threaded into mandrel link bolt hole 32 until stopped by first shank 59. First shank 59 is sized to allow link 52 to pivot about first link bolt 58 with a limited amount of other movement.
Forming press 62 includes forming notches 64, press link bolt hole 66, stop pin hole 68, marker 69, and press handle hole 82. Stop pin 70 is split along its length to allow compression of its diameter. Stop pin 70 is so compressed and inserted for about half of its length into stop pin hole 68. Link 52 is pivotally mounted to forming press 62 with second link bolt 60. Second link bolt 60 is inserted through second link hole 56 and then threaded into press link bolt hole 66 until stopped by second shank 61. Second shank 61 is sized to allow second link bolt 60 and affixed mandrel 28 to pivot in relation to link 52 with a limited amount of other movement. Stop pin 70 orbits around the rounded end of link 52 and limits the total amount of pivoting allowed to mandrel 28 upon contact of stop pin 70 with the straight portions of link 52.
Assembly of tubing bender 10 is completed by threading base handle 74 via base handle threads 76 into base handle hole 72 and press handle 78 via press handle threads 80 into press handle hole 82.
In operation, button 49 is pressed to lift tube retainer 38 to be higher than open face 22. Tube retainer 38 is then rotated clockwise until open stop wall 47 abuts upper recess wall 20. Button 49 and tube retainer 38 are then left unattended such that tube retainer 38 resides in upper recess 23. Starting from the position generally depicted in
An additional embodiment is depicted in
For the embodiment depicted in
The foregoing description and illustrative embodiments of the present invention have been shown on the drawings and described in detail in varying modifications and alternative embodiments. It should be understood, however, that the foregoing description of the invention is exemplary only, and that the scope of the invention is to be limited only to the claims as interpreted in view of the prior art. Moreover, the invention illustratively disclosed herein suitably may be practiced in the absence of any element which is not specifically disclosed herein.
