Rotary bending devices

A rotary bending device for bending workpiece includes a saddle, a rocker, and first and second alignment elements. The saddle includes a longitudinally extending cavity in which the rocker is received, and the rocker rotates relative to the saddle between a neutral position and a bending position for bending the workpiece. The first alignment element is provided on the rocker, and the second alignment element is positioned to engage the first alignment element to limit axial movement of the rocker relative to the saddle during rotation of the rocker between the neutral position and the bending position. The rocker may tangentially contact a bearing surface of the cavity at no more than two lines of tangential contact during rotation. The rocker may further include a longitudinally extending shoulder, and the device may further include a return element positioned to contact the shoulder for biasing the rocker toward the neutral position.

TECHNICAL FIELD

The present invention relates generally to devices for forming materials, and more particularly, to devices for bending malleable materials.

BACKGROUND

Rotary bending devices, also known as rotary benders, are commonly used for forming simple and modified bends in malleable sheet materials, such as sheet metal. Rotary benders generally include a saddle having a cylindrically shaped cavity and a generally cylindrically shaped rocker received within the cavity and being rotatable within the cavity relative to the saddle. In use, rotary benders are generally mounted to a press. During a downstroke of the press, the rocker is forced into contact with the workpiece and rotates within the saddle cavity to bend a portion of the workpiece about an anvil on which the workpiece is supported.

It is generally desirable to stabilize the rocker relative to the saddle while simultaneously minimizing friction generated between the rocker and the saddle during rotation. It is also desirable to limit the range through which the rocker rotates relative to the saddle when returning to a neutral position from a bending position. However, known rotary benders are deficient in these respects and others. Accordingly, there is a need for improvements to known rotary benders.

SUMMARY

A rotary bending device for bending a workpiece according to an exemplary embodiment of the invention includes a saddle, a rocker, and first and second alignment elements. The saddle includes a longitudinally extending cavity in which the rocker is received, and the rocker rotates relative to the saddle between a neutral position and a bending position for bending the workpiece. The first alignment element is provided on the rocker, and the second alignment element is positioned to engage the first alignment element to limit axial movement of the rocker relative to the saddle during rotation of the rocker between the neutral position and the bending position.

A rotary bending device for bending a workpiece according to another exemplary embodiment of the invention includes a saddle having a longitudinally extending cavity provided with a bearing surface, and a rocker received within the cavity. The rocker rotates relative to the saddle between a neutral position and a bending position for bending the workpiece. The rocker tangentially contacts the bearing surface of the saddle at no more than two lines of tangential contact during rotation of the rocker between the neutral position and the bending position.

A rotary bending device for bending a workpiece according to another exemplary embodiment of the invention includes a saddle, a rocker, and at least one return element. The saddle includes a longitudinally extending cavity in which the rocker is received. The rocker has a longitudinally extending shoulder and rotates relative to the saddle between a neutral position and a bending position for bending the workpiece. The at least one return element is positioned to contact the longitudinally extending shoulder of the rocker for biasing the rocker toward the neutral position.

Various additional features and advantages of the invention will become more apparent to those of ordinary skill in the art upon review of the following detailed description of exemplary embodiments taken in conjunction with the accompanying drawings. The drawings, which are incorporated in and constitute a part of this specification, illustrate one or more exemplary embodiments of the invention and, together with the general description given above and the detailed description given below, serve to explain the exemplary embodiments.

DETAILED DESCRIPTION

Referring toFIG. 1, a rotary bender10according to an exemplary embodiment of the invention is shown mounted on a press12, shown schematically. The press12generally includes a drive14, a ram16coupled to and driven linearly by the drive14, and a base18positioned beneath the ram16. The rotary bender10is mounted to a lower surface of the ram16and includes a saddle22and a rocker24, as will be described in greater detail below. A lower tool piece, shown in the form of an anvil20, is coupled to an upper surface of the base18and supports a workpiece (e.g., workpiece92shown inFIGS. 6A-6C), such as a piece of sheet metal or other malleable sheet material. While the press12is shown oriented such that the ram16and rotary bender10move vertically, it will be appreciated that the press12may be positioned in various alternative orientations as desired.

The press12may be controlled to drive the ram16downwardly toward the base18to force the rotary bender10into contact with the workpiece, thereby forming the workpiece against the anvil20. The ram16is then raised from the anvil20so the formed workpiece may be released, and a fresh workpiece may be positioned on the anvil20. A variety of bend types may be formed in the workpiece using the rotary bender10, such as 90 degree bends, square bends, over square bends, under square bends, channel bends, hat bends, zee bends, short leg bends, and “J” bends, for example. The structural features and operation of the rotary bender10are described in greater detail below.

Referring toFIGS. 2-4, the exemplary rotary bender10generally includes a saddle22, a rocker24operatively coupled to the saddle22and rotatable about a longitudinal axis, a gib26coupled to the saddle22and positioned to contact the rocker24for coupling the rocker24to the saddle22, and a return element28for biasing the rocker24toward a neutral rotational position. As described below, the rocker24is rotatable within the saddle22between a neutral position as shown inFIG. 6A, and a bending position for bending a workpiece as shown inFIG. 6B.

The saddle22functions as a base block of the rotary bender10, and includes a base side30that faces the ram16of the press12and an oppositely disposed forming side32that faces the workpiece when mounted for operation, as shown inFIGS. 6A-6C. The forming side32may include one or more through bores34that receive respective fasteners (not shown) for securing the rotary bender10to the ram16. The forming side32further includes a gib landing surface36that supports the gib26, and which may include a threaded bore38for receiving a threaded fastener40for coupling the gib to the saddle22.

A saddle cavity42extends longitudinally through the saddle22, for example spanning a full width of the saddle22, and opens to the forming side32. The saddle cavity42receives the rocker24and includes a bearing surface44that engages an outer surface of the rocker24. The bearing surface44may be provided with a lubricous layer for facilitating rotation of the rocker24within the saddle cavity42and minimizing friction between rocker24and saddle22. In one embodiment, the lubricous layer may be in the form of a dry film lubricant, such as molybdenum disulfide. The dry film lubricant may be applied to the bearing surface44by spraying, for example. In another exemplary embodiment, the lubricous layer may be defined by a plurality of self-lubricating plugs and the bearing surface44may be provided with a bronze alloy layer, as described in greater detail below in connection withFIG. 7. It will be appreciated that various alternative suitable lubricous materials and configurations may be used for lubricating the rocker24and saddle22interface.

The rocker24extends longitudinally and defines a longitudinal axis about which the rocker24rotates relative to the saddle22within the saddle cavity42. The rocker24includes first and second bending lobes46and48that protrude radially and angularly outward from the longitudinal axis of the rocker24, and a forming channel50that extends longitudinally between the bending lobes46,48. As described below, the bending lobes46,48engage a workpiece and bend a skirt portion of the workpiece about an anvil20when the rotary bender10is forced into contact with the workpiece.

The first and second bending lobes46,48include respective first and second forming faces52and54that define respective first and second sides of the forming channel50. While the forming faces52,54are shown herein as being contiguously planar along the length of the rocker24, one or both of the forming faces52,54may be provided with one or more forming features, such as a protrusion (not shown), for forming similarly shaped features in the bent workpiece as desired. It will be appreciated that each of the bending lobes46,48may be formed with any suitable surface area, and that the forming channel50may define any suitable angle between the forming faces52,54, such as 87 degrees for example, for providing a desired bend degree in the workpiece.

The rocker24further includes a shoulder56that extends longitudinally along a full length of the rocker24. In the illustrated embodiment, the shoulder56is defined by a longitudinally extending rectangular notch formed in the rocker24, and is substantially diametrically opposed from the bending lobes46,48and the forming channel50. As best shown inFIGS. 3 and 4, the shoulder56includes a first shoulder surface58and a second shoulder surface60extending substantially perpendicularly to the first shoulder surface58. Each of the shoulder surfaces58,60extends contiguously along a full length of the rocker24, and may be planar.

As described below, the first shoulder surface58contacts a first portion of the return element28for biasing the rocker24toward the neutral position. The second shoulder surface60contacts a second portion of the return element28for preventing rotation of the rocker24beyond the neutral position when rotating from the bending position. Advantageously, the contiguous configuration of the shoulder surfaces58,60allows for the rocker24to be cut to any suitable length for a desired application, while maintaining the functionality of the shoulder56and its shoulder surfaces58,60for effectively engaging the return element28. In other words, the shoulder56is formed such that the return element28may effectively engage the shoulder56at any position along the length of the rocker24.

The gib26is coupled to the saddle22at the gib landing surface36, for example by a threaded fastener40, and is positioned to contact the rocker24for retaining the rocker24within the saddle cavity42. As best shown inFIG. 4, the gib26includes an angled contact face64that tangentially contacts an outer surface of the rocker24extending between the first bending lobe46and the second shoulder surface60. While only one gib26is shown, it will be appreciated that any suitable quantity of gibs26may be provided for coupling the rocker24to the saddle22depending on the length of the rocker24and the saddle22, each gib26securing a respective longitudinal portion of the rocker24to a respective longitudinal portion of the saddle22.

As best shown inFIGS. 3 and 4, the rotary bender10includes a plurality of axial alignment elements for limiting axial movement of the rocker24relative to the saddle22during rotation of the rocker24within the saddle cavity42. In the illustrated embodiment, a first alignment element in the form of a rib66projects outwardly from the angled contact face64of the gib26, and a second alignment element in the form of a circumferential slot68is provided on the rocker24. As shown inFIG. 3, the circumferential slot68extends circumferentially about the longitudinal axis of the rocker24between the first bending lobe46and the second shoulder surface60. The rib66may be formed with a substantially triangular shape and projects radially inward into the circumferential slot68. The circumferential slot68may be formed with an axial width sufficient to accommodate an axial thickness of the rib66with at least a slip fit interface, such that the rocker24may rotate freely relative to the gib26with minimal generation of friction. The circumferential slot68may also be formed with a radial depth sufficient to accommodate a maximum dimension of the rib66in a direction outwardly from the contact face64.

In an alternative embodiment in which the rotary bender10includes multiple gibs26for securing the rocker24within the saddle cavity42, the rocker24may be provided with one or more circumferential slots68that receive the ribs66of respective gibs26. Additionally, while the illustrated embodiment includes a rib66provided on the gib26and a circumferential slot68provided in the rocker24, a reverse configuration may alternatively or additionally be employed. Moreover, various alternative axial alignment elements other than ribs and circumferential slots may be suitably used.

Still referring toFIGS. 3 and 4, the return element28generally includes a plunger70and a biasing element shown in the form of a compression return spring72. The plunger70is received within a plunger passageway74formed in the saddle22. The passageway74opens at a first end to a base portion of the saddle cavity42along the bearing surface44, and at a second end to a side surface75of the saddle22. The plunger70is slidable within the passageway74and is biased by the return spring72toward the saddle cavity42such that the plunger70exerts a substantially constant force on the first shoulder surface58of the rocker24for biasing the rocker24toward the neutral rotational position, shown inFIG. 6A. The plunger70may include a centrally formed internal channel76sized to receive and axially constrain a portion of the return spring72. An anchor element, shown in the form of a set screw78, may be positioned within an outer end of the passageway74for retaining the return spring72within the passageway74and maintaining the bias force exerted by the plunger70on rocker shoulder surface58.

As shown inFIG. 4, the plunger70generally includes a tip80and a side surface82. The plunger tip80contacts the first shoulder surface58of the rocker24for biasing the rocker24toward the neutral rotational position (FIG. 6A). The plunger side surface82is adapted to contact the second shoulder surface60of the rocker24when in the neutral rotational position. In this manner, the plunger side surface82functions as a mechanical stop and prevents rotation of the rocker24beyond the neutral position when the rocker24rotates from the bending position (FIG. 6B) under the bias force exerted by the plunger tip80and return spring72.

The plunger70may be formed with a noncircular cross-section, such as the rounded rectangular cross-section shown inFIG. 4. The rounded rectangular cross-section of the plunger70defines a side surface82having first and second planar faces83a,83boppositely disposed from one another. As best shown inFIGS. 6A and 6C, when the rocker is in the neutral position, the first planar face83aof the plunger70confronts the second shoulder surface60of the rocker24, while the second planar face83bconfronts a planar base surface of the plunger passageway74. Advantageously, the first planar face83aof the plunger side surface82contacts the second shoulder surface60of the rocker24with a greater area of contact than a plunger having a fully rounded side surface. Accordingly, the planar faces83a,83bof the plunger side surface82provide for decreased stresses exerted on the plunger70, and thus improved anti-rotational support for the rocker24in the neutral position. It will be appreciated that the plunger70may be formed with various alternative cross-sectional shapes as desired. For example, the alternative embodiment ofFIG. 7shows a plunger118having a circular cross-section.

The plunger passageway74is sized and shaped to receive the plunger70. For example, the plunger70and plunger passageway74may both be formed with noncircular cross-sections, as shown in the embodiment ofFIG. 4. Alternatively, the plunger70and passageway74may be formed with circular cross-sections, as described in greater detail below in connection withFIG. 7. In embodiments in which the plunger70is formed with a noncircular cross-section, such as the embodiment ofFIG. 4, the passageway74may include a centrally formed circular bore portion, best shown inFIGS. 2 and 3, that receives the return spring72and the set screw78. It will be appreciated that the plunger passageway74may be formed with various alternatively shaped cross-sections to accommodate a correspondingly shaped cross-section of the plunger70.

While the rotary bender10is shown herein with a single return element28, any suitable quantity of return elements28and corresponding plunger passageways74may be provided depending on the length of the rocker24and the saddle22. For example, a return element28may be positioned at each location of a gib26. Advantageously, as described above, the rocker shoulder56extends contiguously along a length of the rocker24and is adapted to engage one or more return elements28at generally any location along the length of the rocker24. That is, the available positioning of a return element28along the length of the saddle cavity42is independent of the rocker feature that contacts the return element28, namely, the rocker shoulder56.

Referring toFIGS. 5A and 5B, additional details of the saddle cavity42and the interface of the rocker24with the saddle22and the gib26will now be described. The saddle cavity42is formed with a noncircular cross-section, as compared to the substantially circular cross-section with which the rocker24is formed. Advantageously, this configuration minimizes the contact area, and thus friction generated, between the saddle22and the rocker24.

In an exemplary embodiment, as shown inFIG. 5B, the noncircular cross-sectional shape of the saddle cavity42may be defined by first, second, and third overlapping circular arcs A1, A2, and A3. Each of the arcs A1, A2, A3includes a corresponding center indicated by C1, C2, and C3, respectively, and is defined by a corresponding radius indicated by R1, R2, and R3, respectively. The radii R1, R2, R3may be equal to one another, for example. As shown inFIG. 5B, the first arc A1is positioned centrally and defines an innermost base portion84of the saddle cavity42. The second and third arc centers C2, C3are positioned outwardly from the first arc center C1in a direction away from the base portion of the saddle cavity42, and are equidistant from the first arc center C1. The second and third arcs A2, A3define corresponding side portions86,88of the saddle cavity42. Accordingly, the bearing surface44may be understood to have an innermost base portion84defined by the first arc A1, a first side portion86defined by the second arc A2, and a second side portion88defined by the third arc A3.

The junction of the base portion84with the first side portion86defines a first line X1, extending along the length of the saddle cavity42, at which the rocker24tangentially contacts the bearing surface44. Similarly, the junction of the base portion84with the second side portion88defines a second line X2, extending along the length of the saddle cavity42, at which the rocker24tangentially contacts the bearing surface44.

As shown best inFIG. 5A, the rocker24tangentially contacts the angled contact face64of the gib26at a third line X3. It will be understood that the contact lines X1, X2, X3are fixed relative to the saddle22and the gib26. Accordingly, specified circumferential portions of the outer surface of the rocker24may rotate into and out of engagement with the contact lines X1, X2, X3as the rocker24rotates between the neutral position (FIG. 6A) and the bending position (FIG. 6B). Moreover, depending on the rotational position of the rocker24between the neutral and bending positions, the rocker shoulder56may be oriented relative to the bearing surface44such that the rocker24contacts the bearing surface44at only the first contact line X1. In this regard, it will be appreciated that the rocker24may tangentially contact the bearing surface44at no more than two lines of tangential contact at any given rotational position of the rocker24relative to the saddle22.

Referring toFIGS. 6A-6C, an exemplary bending operation using rotary bender10is shown. Similar toFIG. 1, the rotary bender10is shown mounted to the underside of a ram16, using a key90. A workpiece92having a body portion94and a skirt portion96to be bent is positioned on the anvil20such that the skirt portion96extends beyond a beak98of the anvil20. Though not shown, the skirt portion96may be slightly pre-bent relative to the body portion94. As noted above, while the ram16is shown herein performing vertical movements, it will be appreciated that the press12driving the ram16may be oriented as desired to achieve various alternative directions of movement in which the ram16moves linearly relative to the anvil20. Accordingly, the terms “upstroke,” “downstroke,” “upward,” “downward,” “raise,” “lower,” and similar terms as used herein are not intended to limit the scope of the invention to a particular orientation of the press12and rotary bender10.

As shown inFIG. 6A, the rotary bender10is spaced from the workpiece92, with the rocker24retained in the neutral rotational position by the return element28. In particular, the tip80of the plunger70contacts and exerts an outwardly directed force, transferred from the return spring72, on the first rocker shoulder surface58so as to urge the rocker24in a counter-clockwise rotational direction, for example. The second rocker shoulder surface60contacts the first planar side face83aof the plunger70, which prevents the rocker24from rotating, in the exemplary counter-clockwise direction, beyond the neutral position shown inFIG. 6A.

While the rocker24is in its neutral rotational position, the ram16initiates a downward stroke in which the rotary bender10is moved linearly toward the workpiece92, thereby forcing the bending lobes46,48of the rocker24into contact with the workpiece92. The second bending lobe48clamps the body portion94of the workpiece92against an upper surface of the anvil20and the first bending lobe46engages, or at least proximately confronts, the skirt portion96. As the ram16continues to drive the rotary bender10toward the anvil20, the rocker24rotates within the saddle cavity42so that the first bending lobe46bends the skirt portion96around the anvil beak98and toward a side surface of the anvil20, as shown inFIG. 6B. Simultaneously, the first rocker shoulder surface58forces the plunger70into the plunger passageway74, thereby compressing the plunger spring72. This compression of the spring72causes the plunger tip80to continuously engage and exert an outwardly directed force on the rocker shoulder surface58.

As shown inFIG. 6B, the rocker24has rotated fully into its bending rotational position, in which the first forming face52of the rocker24clamps the skirt portion96against the side surface of the anvil20, and the second forming face54clamps the body portion94against upper surface of the anvil20, thereby bending the skirt portion96relative to the body portion94. As shown, the bent portion of the workpiece92is received within the rocker forming channel50. The forming channel50and the anvil beak98may be formed with similar angles so as to provide the skirt portion96with any desired degree of overbend, such as up to three degrees, for example.

As shown inFIG. 6C, once the skirt portion96of the workpiece92has been fully bent, the ram16initiates an upstroke to raise the rotary bender10away from the bent workpiece92. As the ram16rises, the rocker24is allowed to rotate back toward its neutral rotational position. More specifically, as the rocker24rises with the ram16away from the bent workpiece92, the force exerted on the plunger70by the compressed return spring72is transferred by the plunger tip80to the first rocker shoulder surface58, thereby urging the rocker24to rotate counter-clockwise so the first bending lobe46disengages the skirt portion96. As a result, the skirt portion96is allowed to spring slightly outward from the anvil20into its final bent orientation, such as a 90 degree bend relative to the body portion94, for example. It will be appreciated that the bending lobes46,48of the rocker24and the anvil beak98may be formed with any suitable angles to achieve various alternative final bend configurations in the workpiece92. As the rocker24reaches its neutral position, the second shoulder surface60abuts the first planar face83aof the plunger70to prevent the rocker24from rotating beyond the neutral position, as described above.

Referring toFIG. 7, a rotary bender110according to another exemplary embodiment of the invention is shown, for which similar reference numerals refer to similar features of the rotary bender10. The rotary bender110is similar in construction and function to rotary bender10, except as otherwise described below.

The lubricous layer provided between the bearing surface44and the rocker24is defined by a plurality of self-lubricating plugs112, which may be formed of graphite, for example. The self-lubricating plugs112are received within ports114that extend through the bearing surface44and into the saddle22. The ports114may be arranged in rows formed along each of the first and second tangential contact lines X1, X2(seeFIGS. 5A and 5B). Additionally, the bearing surface44may be coated with or otherwise formed of a bronze alloy, such as aluminum bronze, to enhance the lubricous effect.

A return element116of the rotary bender110includes a plunger118and a plunger passageway120having circular cross-sections. The plunger118includes a bore that receives and retains a portion of the return spring72, similar to channel76of plunger70. Advantageously, the circular cross-sectional shapes of the plunger118and passageway120provide for increased ease of manufacturing and decreased material use relative to similar features having noncircular cross-sectional shapes. The circular cross-sectional shape of the plunger118may result in tangential contact between a side surface122of the plunger118and the second shoulder surface60of the rocker24when the rocker24is in the neutral position.

While the present invention has been illustrated by the description of specific embodiments thereof, and while the embodiments have been described in detail, it is not intended to restrict or in any way limit the scope of the appended claims to such detail. The various features discussed herein may be used alone or in any combination. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and methods and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the scope of the general inventive concept.