Self cutting wire bender

A device for bending wire that includes a pin extending from an upper surface of a plate, a shaft extending through a center aperture of the plate and terminating in a bend head, a sleeve rotatably disposed around the shaft, a first motor for rotating the plate about the shaft, and a second motor configured to move the plate between extended, retracted and intermediate positions along the shaft. The plate positioned in the extended position and rotating causes the first pin to travel in front of a wire aperture of the bend head. The plate positioned in the intermediate and the retracted positions and rotating causes the first pin to travel underneath the wire aperture. The plate positioned in the retracted position causes the plate to engage with the sleeve such that rotation of the plate causes rotation of the sleeve.

FIELD OF THE INVENTION

The present invention relates to devices that bend wire into desired shapes.

BACKGROUND OF THE INVENTION

Wire benders are devices that bend wire into desired 2-dimensional or 3-dimensional shapes. Early wire benders provided a mechanism that allowed a user to manually bend wire into desired shapes. See for example U.S. Pat. Nos. 4,091,845 and 5,809,824. More recently, motorized wire benders have been developed that use a moving pin under motor control to bend wire, some even operating under computer control. See for example U.S. Pat. No. 5,088,310. Drawbacks of such devices, however, include excessive expense, complexity and size. Additionally, such devices are difficult to set up and operate for each desired wire shape, especially when the wire shape is completed and needs extraction from the wire feed (which traditionally is done manually by hand).

There is a need for a wire bender device design that is simple and relatively inexpensive and easy to operate, so that wire shapes can be effectively and efficiently created and extracted.

BRIEF SUMMARY OF THE INVENTION

The aforementioned problems and needs are addressed a device for bending wire that includes a plate (with upper and lower surfaces and a center aperture extending there between, and a first pin extending from the upper surface), a shaft extending through the center aperture and terminating in a bend head where the bend head includes a wire aperture configured to pass a wire and first and second bend surfaces positioned adjacent the wire aperture, a sleeve rotatably disposed around the shaft, a first motor configured to rotate the plate about the shaft in opposing first and second rotational directions, and a second motor configured to move the plate between an extended position and a retracted position, and an intermediate position there between, along the shaft. The plate positioned in the extended position and rotating in the first rotational direction causes the first pin to travel in front of the wire aperture. The plate positioned in the intermediate and the retracted positions and rotating in the first rotational direction causes the first pin to travel underneath the wire aperture. The plate positioned in the retracted position causes the plate to engage with the sleeve such that rotation of the plate in the first rotational direction causes rotation of the sleeve in the first rotational direction and rotation of the plate in the second rotational direction causes rotation of the sleeve in the second rotational direction.

The device for bending wire can include a plate (with upper and lower surfaces and a center aperture extending there between and a first pin extending from the upper surface), a shaft extending through the center aperture and terminating in a bend head where the bend head includes a wire aperture configured to pass a wire and first and second bend surfaces positioned adjacent the wire aperture, a sleeve rotatably disposed around the shaft, a first motor configured to rotate the plate about the shaft in opposing first and second rotational directions, a second motor configured to move the plate between an extended position and an intermediate position along the shaft, and a third motor configured to rotate the sleeve about the shaft in the opposing first and second rotational directions. The plate positioned in the extended position and rotating in the first rotational direction causes the first pin to travel in front of the wire aperture. The plate positioned in the intermediate position and rotating in the first rotational direction causes the first pin to travel underneath the wire aperture. The shaft includes a cavity therein in communication with second apertures in a sidewall of the shaft, and the sleeve including a cam surface facing the shaft. A plunger is disposed in the cavity and has a second cam surface and an upper surface. Ball bearings are each disposed in one of the apertures and between the cam surface and the second cam surface. Rotation of the sleeve in the first rotational direction causes the cam surface to move the ball bearings toward a center of the cavity of the shaft and engaging the second cam surface for driving the plunger upwardly in the cavity. Rotation of the sleeve in the second rotational direction causes the cam surface to allow the ball bearings to move away from the center of the cavity of the shaft for allowing the plunger to move downwardly in the cavity.

DETAILED DESCRIPTION OF THE INVENTION

The present embodiment is a desktop sized wire bender that converts drawn curves into bent wire having 2-dimensional or 3-dimensional shapes. The wire bender1is shown inFIG. 1, and includes a housing10having a top plate12.

The top plate12serves as a work surface on which the wire manipulation components are positioned. These components include two pairs of feed wheels, with each pair including two wheels14aand14bthat pinch and manipulate the wire fed there between.

A bend head20is positioned to receive the wire fed from the pairs of feed wheels. The bend head20is better shown inFIG. 2, and includes an aperture22through which the wire can be fed to hold the wire in place while it is being bent. Bend head20also includes a pair of bend surfaces24aand24b, one on each side of the aperture22. Above the aperture22and between the bend surfaces24a/24bis a cutting edge26(preferably enhanced by a less than 90 degree angle between the top surface of the aperture and the side wall which defines the cutting edge). The bend head20is positioned at the top of a shaft28.

Shaft28protrudes through a center aperture32of a plate30, as best shown inFIGS. 3-4. Plate30preferably has a circular out edge. Plate30includes an upwardly protruding pin34closely adjacent the aperture32. Pin34can be integrally formed as part of plate30, or part of an assembly that mounts to plate30as best shown inFIG. 3. Pin34travels (translates) in an arch shape path relative to the bend head20by rotation of the plate30about its center aperture32. Shaft28also protrudes through a hollow sleeve38to be explained in further detail below.

FIG. 4shows wire40extending through the aperture22of bend head20and out beyond the bend surfaces24a/24b. The pin34is shown positioned at the point it makes initial contact with the wire40. The plate30is then rotated counterclockwise from the position shown inFIG. 4, which causes the pin34to travel in front of aperture22and push on wire40(wrapping the wire40around bend surface24a) until the desired bend shape is achieved in the wire. At that point, pin34retreats away from wire40by rotating plate30in the opposite direction. Thereafter, the wire40is advanced by the feed wheels14a/14bto the next target location of the wire to be bent. To implement bends in the opposite direction, the plate30lowers vertically down to a semi-retracted (intermediate) position so that the pin34can travel underneath the aperture22and therefore underneath the wire without engaging it, where plate30then rises vertically to its raised (extended) position and rotates clockwise so that pin34passes in front of the aperture22and engages wire40from the other side and pushes on wire40(wrapping the wire around bend surface24b) until the desired bend shape is achieved in the wire.FIG. 5Ashows the plate30in its raised (extended) position (where pin34will engage with and bend wire40upon rotation of the plate30).FIG. 5Bshows the plate30in a fully retracted position used for cutting as further described below. The intermediate position is between those shown inFIGS. 5A and 5B.

FIG. 6shows that shaft28is disposed inside of sleeve38, which rotates about shaft28. Sleeve38includes a sloping cam slot42which engages with a cam pin44extending out of shaft28. Rotation of the sleeve38about shaft28in one direction causes pin44to engage with the upper sloping side of cam slot42to move the sleeve upwardly relative to the shaft28(from a retracted position to an extended position). Rotation of the sleeve38about shaft28in the other direction causes pin44to engage with the lower sloping side of cam slot42to move the sleeve downwardly relative to the shaft28(from the extended position to the retracted position).FIG. 7Ashows sleeve38in the retracted position.FIG. 7Bshows sleeve38in its intermediate position (e.g., traveling from the retracted position to the extended position).FIG. 7Cshows sleeve38in the extended position. As the sleeve reaches the extended position, the sleeve's top edge engages with the wire40extending out of the aperture22, pressing it against cutting edge26, which cuts the wire off as the top edge of sleeve38passes cutting edge26(as shown inFIG. 7C). The top edge of sleeve38includes a notch or recess46so that the sleeve does not engage the portion of the wire feeding into the other side of aperture22. This configuration is advantageous because it cuts the wire at a location directly adjacent the bend surfaces24a/24b, which is ideal for those desired wire shapes where the wire is to end and be cut at or very near the last bend shape. This cutting capability provides accurate cutting, and means that the user need not manually cut the wire which could be time consuming and inaccurate.

Rotation of sleeve38is accomplished by lowering plate30to its retracted position so that its center aperture32engages with a flange48of sleeve38. Aperture32and flange48have shapes that match each other sufficiently so that rotating plate30causes aperture32engaged with flange48to rotate sleeve38. The non-limiting example in the figures shows aperture32having a generally square shape matching a generally square shape of the lower portion of flange48. This configuration is advantageous because the same motor used to rotate plate30for bending wire40can also be used to rotate and raise sleeve38for cutting wire40.

FIGS. 8-10illustrates the structure used to raise and lower plate30, and rotate plate30. The plate30is connected to sleeve50that includes teeth52on its outer circumference. Gear54is engaged with teeth52and is driven by motor56to drive sleeve50and plate30vertically between three positions (a fully raised position so that pin34engages with wire40, a semi-retracted position that allows the pin to pass underneath the wire without engaging it, and a fully retracted position wherein plate aperture32engages with sleeve flange48for rotating and raising sleeve38for cutting the wire. Rotation of plate30is provided by belt58which is engaged with sleeve50. Preferably, belt58is a toothed timing belt that engages with a toothed pulley60connected to the sleeve50. Motor62drives belt58to rotate sleeve50and plate30. This means that three actions (raising/lowering plate30, rotating plate30, and rotating sleeve38for vertical movement) are accomplished using only two motors, driving down the complexity, size and cost of the wire bender1. Moreover, teeth52preferably extend around the entire circumference of sleeve50, so that the raising/lowering of plate30can be performed independently and concurrently with rotation of plate30(e.g., so that the plate30can maintain engagement with the rising flange48as sleeve38travels vertically up and down).

FIGS. 11-22illustrate an alternate embodiment which also utilizes the rotation of the plate30to perform the wire cutting.FIGS. 11-13show the bend head120which is similar to bend head20, except the cutting edge126is spaced further back from the bend surfaces124a/124band adjacent a center aperture166that meets wire aperture122. The bend head120is positioned at the top of a shaft128. Shaft128protrudes through center aperture32of plate30, as best shown inFIG. 14. Shaft128is hollow and has an interior cavity168that is in communication with center aperture166and with apertures170formed in the sidewall of shaft128, as best shown inFIGS. 11-12. Three apertures170are shown, but the number can vary.

A sleeve164having an irregularly shaped interior sidewall172is rotatably disposed around shaft128and over apertures170, as best shown inFIGS. 15-19. The outer surface of sleeve164includes cavities174formed therein. Three cavities174are shown and are in the form of open notches, but the number can vary and they could be fully enclosed holes. The plate30includes pins176extending down from its lower surface for engaging with cavities174as described further below. Three pins176are shown, but the number can vary. A plunger178is disposed inside the interior cavity168of shaft148, as best shown inFIGS. 20B-22B and 23. Plunger178includes a rounded bottom surface180and an upwardly extending pin182that protrudes through aperture166of the bend head120. Pin182preferably includes a concave top surface182afor engaging wire40. A spring184is disposed inside cavity168of shaft128and provides a downward resilient force on the plunger178(e.g., the spring presses downwardly on a shoulder179of plunger178from which pin182extends). Ball bearings186are disposed in apertures170of shaft128, and between (and in contact with) the interior sidewall172of sleeve164and the rounded bottom surface180of plunger178, as best shown inFIGS. 20A-22A. Three ball bearings186are shown, but the number can vary.

FIG. 17shows the plate30in its raised/extended position (where pin34will engage with and bend wire40upon rotation of the plate30).FIG. 18shows the plate30in the intermediate position (where pin34can pass underneath the wire40without engaging it upon rotation of the plate30).FIG. 19shows the plate in a fully retracted position (where pins176of plate30engage with cavities174of sleeve164so that sleeve164is rotated by the rotation of plate30).

As with the previous embodiment, rotation of the plate30is used to both bend the wire and to cut the wire. This is achieved by a ball and cam mechanism that translates the radial torque of the plate30to a vertical force in the upward direction on the plunger178. The wire40is then cut by simple shearing action between the pin182of the plunger178. Specifically, in the present embodiment, shaft128houses plunger178, ball bearings186and spring184. Sleeve164rotates around shaft128and is constrained axially by retaining rings188. The shaft128is fabricated preferably out of tool steel alloys to ensure durability and strength. Plunger178and rotating sleeve164are fabricated of tool steels or high alloy steels suitable for the high pressures and stresses that will be present. Ball bearings186are either made of steel alloys or ceramics from any of the different carbide families. These material selections are examples and not intended to be limiting.

The cam and ball design allows for 3 different heights for operation for plate30. The raised/extended position of plate30positions pin34to engage with and bend the wire40(seeFIG. 17). The intermediate position of plate30allows pin34to pass under the wire40without engaging the wire, and without any cutting action (seeFIG. 18). The retracted position of plate30causes pins176of plate30to engage with cavities174of sleeve164so that subsequent rotation of plate30causes rotation of sleeve164(seeFIG. 19).

When the plate30is in the retracted position and rotates, it rotates sleeve164engaged therewith, causing the sleeve164to press inwardly on ball bearings186. Specifically, the interior sidewall172of sleeve164is a cam surface having a tri-lobe or rounded triangle shape, and translates pure rotation of the plate30into radial travel of the ball bearings as seen inFIGS. 20A-22A. This geometry also determines both the amount of inwards radial travel of the ball bearings and the mechanical advantage with which the bending torque of plate30is converted into inwards radial force on the ball bearings. Therefore, the geometry of the tri-lobe cam surface172can be optimized for specific travels or forces required at the plunger.

When the ball bearings186move inwards under the force exerted by cam surface172, the ball bearings186press with equal force against the rounded bottom surface180of plunger178(i.e., a second cam surface), which in turn forces the plunger178to travel upwards, as shown inFIGS. 20B-22B. The round on round interface between the round ball bearings186and rounded bottom surface180of plunger178minimizes friction and maximizes mechanical advantage on the upwards motion, which allows the mechanism to apply enough force to cleanly cut the wire using shearing action. The upward motion of the plunger causes the plunger's pin182to engage with and cut wire40by a shearing action with cutting edge126of bend head120(seeFIG. 22B). The cutting action causes the cut wire to naturally eject itself due to the induced shearing stresses. After cutting, the plate30is rotated in the opposite direction so that the plunger178and its pin182return to its resting position under the resilient force of spring184(seeFIG. 20B). This spring-induced retraction force also forces the ball bearings186to fully retract outwards until they come to rest on the corners of the tri-lobe features of the rotating sleeve's cam surface172. The spring184can be either a compression spring, a tension spring, a constant force spring, or a combination of. Once the rotating sleeve164has come to its resting position (FIGS. 20A and 20B), the plate32can be lifted to either the intermediate position (FIG. 18) for pin positioning or the extended position for wire bending (FIG. 17).

The number of ball bearings186can vary, but having three ball bearings186pushing out into the cavities of a tri-lobe cam surface172presents the secondary advantage of achieving high angular repeatability of the resting position of the rotating sleeve164, which then enables a manufacturer to automate a cutting sequence, in the case of a CNC machine, knowing that the rotating sleeve164will always be accurately found in a specific position for engagement.

The ball bearings186are housed in three equally spaced apertures170shown inFIGS. 11-12, bored in the body of the shaft128. The size and surface finish of these holes affect the friction losses of the mechanism for which special provisions should be taken to ensure the free fit and free motion of the ball bearings186through the apertures170. The plunger178is shown to have a rounded bottom surface180for engaging with ball bearings186. However, bottom surface180could instead have a different shape, such as conical, convex, or pyramidal. Alternatively, the bottom surface of plunger178could be flat and rest on a larger ball bearing190disposed in the cavity168of shaft128that is engaged with the smaller ball bearings186, as shown inFIG. 23A-23C. During the cutting motion, the plunger178travels upwards inside the cavity168bored concentrically into the shaft128, which has been machined and finished to a size that allows for free motion but with limited clearance such that the plunger178cannot rock or tilt beyond acceptable ranges.

Preferably both the plunger's pin182and the aperture166through which it extends have rectangular cross sections, which allow for vertical motion with limited friction, yet prevents any rotation of the plunger178. The concave upper surface182aof the plunger's pin182preferably matches or closely resembles the shape of the wire being cut to achieve a shearing action that is closer to a quill-on-quill system. Both the relief and contour can be added and tuned to optimize the quality of the cut, minimize or eliminate flash and burrs, and improve the durability of the plunger. As stated above, the rotating sleeve164could have more or less lobes than the three shown in the figures, depending on how many ball bearings186are used to distribute the loads. While plate30has pins176engaging with cavities174in sleeve164, the opposite configuration could be implemented (i.e., pins extending from sleeve164could engage with cavities (i.e., holes) in plate30). The number of pins176can vary from less than three (i.e., 1 or 2) or greater than 3.

All of the above described embodiments can use the same two motors and related features as described above with respect to the first embodiment ofFIGS. 1-10for vertically moving the plate, and for rotating the plate for wire bending and cutting, along with other features useable in operation (e.g., housing10, top plate12, feed wheels14, etc.).

FIGS. 25A-25Billustrate a further embodiment, where a third motor is used to rotate sleeve164for driving plunger178, thereby negating the need for the plate30to have a fully retracted position in which the plate30engages with the sleeve164. Instead, a third motor192(separate from motor56used to raise/lower plate32and motor62used to rotate plate) is configured to rotate sleeve164via belt194. With this embodiment, sleeve cavities174and pins176are omitted. Spring184can remain to assist the motor192in driving the plunger178downward, or can be omitted as well. While the use of motor192is shown with flat bottomed plunger178and ball bearing190, the motor192and belt194configuration can also be used with plunger178with rounded bottom surface180and no ball bearing190as well.

FIGS. 26A-26Billustrate a further embodiment, which is the same as the embodiment ofFIGS. 25A-25B, except instead of using a belt, a gear196rotated by motor192engages with teeth164aformed on the surface of sleeve164for rotating sleeve164.

FIGS. 27A-27Dillustrate a further embodiment, wherein instead of a spring or gravity used to drive the plunger178downwardly, rotation of sleeve164provides both the upward and downward force on plunger178. Specifically, plunger178includes two cam surfaces178aand178b, that engage with ball bearings186aand186brespectively. The cam surface172of sleeve164is elliptical, and rotation of sleeve164drives ball bearings186ainwardly while ball bearings186btravel outwardly, and vice versa. When ball bearings186aare driven inwardly, they push plunger178upwardly by engaging cam surfaces178a, as shown inFIGS. 27A and 27B(arrows showing direction of movement). When ball bearings186bare driven inwardly, they push plunger178downwardly by engaging cam surfaces178b, as shown inFIGS. 27C and 27D(arrows showing direction of movement). This embodiment can be used with the two motor or the three motor configurations described above.

It is to be understood that the present invention is not limited to the embodiment(s) described above and illustrated herein, but encompasses any and all variations falling within the scope of any claims. For example, references to the present invention herein are not intended to limit the scope of any claim or claim term, but instead merely make reference to one or more features that may be covered by one or more of the claims. Materials, processes and numerical examples described above are exemplary only, and should not be deemed to limit the claims. Further, as is apparent from the claims and specification, not all method steps need be performed in the exact order illustrated or claimed. While plunger178is shown as unitary, it could instead be several distinct parts confined in cavity168.

It should be noted that, as used herein, the terms “over” and “on” both inclusively include “directly on” (no intermediate materials, elements or space disposed there between) and “indirectly on” (intermediate materials, elements or space disposed there between). Likewise, the term “adjacent” includes “directly adjacent” (no intermediate materials, elements or space disposed there between) and “indirectly adjacent” (intermediate materials, elements or space disposed there between), “mounted to” includes “directly mounted to” (no intermediate materials, elements or space disposed there between) and “indirectly mounted to” (intermediate materials, elements or spaced disposed there between), and “engaged with” includes “directly engaged with” and “indirectly engaged with” (intermediate components connect the elements together).