Rotating log clamp

A rotating log saw clamp for clamping a product roll to be sawn. The rotating log saw clamp includes a first portion disposed for rotation about an axis and a second portion disposed for rotation with the first portion and movable relative to the first portion between an open position and a clamping position. The second portion is rotatable from the clamping position to the open position by relative rotation of the first and second rotating portions in a common direction.

BACKGROUND OF THE INVENTION

The invention generally relates to clamps. More particularly, the invention relates to clamps for securing rolls of paper (commonly referred to in the trade as “logs”) during sawing processes.

Many types of paper are produced in logs for ease of manufacture. As used herein and in the appended claims, the term “log” is meant to include rolls of paper products such as napkins, paper towels, facial tissue, toilet tissue, newsprint, and the like. Also, because the present invention is not limited to rolls of paper products, the term “log” is meant to include rolls of products which are made from other materials including without limitation cellophane, plastic sheeting, and other synthetic materials, fabric, woven, and non-woven textiles and cloth, foil, etc., regardless of product porosity, density, and dimensions. These logs must typically be sawn into shorter rolls more readily used by consumers. Automating the sawing process is necessary to achieve satisfactory production rates. Typically, automated sawing processes have utilized a reciprocating or orbital radial or band saw in combination with a stationary log clamp.

Bias cutting and inadequate clamping of the log reduce the yield of prior art sawing processes. Tremendous pressure is placed on the saw blade as it cuts into the log because the saw blade is normally toothless to avoid shredding the log. Thus, this cutting process often requires greater force to shear the log than a process involving a blade with teeth, increasing bias cutting and log core crushing problems.

Prior art clamps often secure a log using elastic straps or grippers during the sawing process, and can often be adjusted for varying diameters. However, these clamps may allow slight movement during the sawing process, especially for logs of large diameter and heavy density. A clamp should hold the log stable when the blade applies large forces while penetrating the log.

Various clamping methods and apparatus have been used in the past. Nevertheless, a new clamping method and apparatus that provides enhanced performance and results in improved product quality would be welcomed by those in the art.

SUMMARY OF THE INVENTION

Some embodiments of the present invention provide for a clamping apparatus that includes a clamp having a first portion rotatable about an axis and a second portion rotatable about the axis and with respect to the first portion between a first position in which the clamp is tightened with respect to the product roll in the clamp and a second position in which the clamp is loosened with respect to the product roll in the clamp.

In some embodiments, the invention provides a rotating log saw clamp for clamping a product roll to be sawn. The rotating log saw clamp in such embodiments includes a first portion disposed for rotation about an axis and a second portion disposed for rotation with the first portion and movable relative to the first portion between an open position and a clamping position. The second portion is rotatable from the clamping position to the open position in rotation of the first and second rotating portions in a common direction.

In other embodiments, the invention provides a method of clamping a product roll to be sawn in a rotating log saw. The method includes rotating first and second portions in a common direction about an axis, and rotating the second portion relative to the first portion to move the second portion from a clamping position to an open position during rotation of the first and second rotating portions in a common direction.

In another aspect of the present invention, some embodiments provide a rotating log saw clamp for clamping a product roll to be sawn in which the rotating log saw clamp includes a first ring adapted to clamp and rotate about an axis a product roll to be sawn and a second ring rotatably coupled to the first ring. The second ring is driven separately from the first ring for rotation relative to the first ring as the first and second rings rotate together in a common direction. The second ring is rotated relative to the first ring to adjust the clamping of the product roll.

In some embodiments, the invention provides a method of clamping a product roll to be sawn in a rotating log saw clamp, wherein the method includes rotating first and second rings in a common direction about an axis, driving the second ring separately from the first ring for rotation relative to the first ring during rotation of the first and second rings together in a common direction, and adjusting the clamping of the product roll.

Also, in some embodiments, the invention provides a rotating log saw clamp for clamping a product roll to be sawn, wherein the rotating log saw clamp includes a frame, a housing rotatably coupled to the frame about an axis, a plurality of clamps positioned about the axis and movable relative to the axis, and a ring rotatably coupled to the housing about the axis. The housing is disposed for rotation with a product roll to be sawn. The ring is rotatable independently of the housing. The ring is rotatable relative to the housing in common rotation of the housing and ring. The ring is movable relative to the housing to move the plurality of clamps relative to the axis.

In still other embodiments, the invention provides a method of clamping a product roll to be sawn in a rotating log saw clamp, wherein the method includes rotating a housing and a ring in a common direction about a common axis, rotating of the ring independently of the rotation of the housing, rotating the ring relative to the housing during common rotation of the housing and ring, and moving a plurality of clamps relative to the axis by rotating the ring relative to the housing.

Further objects of the present invention together with the organization and manner of operation thereof, will become apparent from the following detailed description of the invention when taken in conjunction with the accompanying drawings wherein like elements have like numerals throughout the drawings.

DETAILED DESCRIPTION

Referring to the figures, and more particularly toFIGS. 1,2, and3, a log saw assembly10constructed in accordance with an exemplary embodiment of the present invention is illustrated. Although the embodiments of the present invention described below and illustrated in the figures are presented with reference to the log saw assembly10, it should be noted that the present invention can also be employed in other types of equipment that require clamping operations, whether those operations include sawing or not.

The log saw assembly10includes a frame14, a log saw clamping assembly18, and a log saw having a log saw blade22(schematically illustrated inFIGS. 2 and 3). In some embodiments, as discussed further below, multiple log saw assemblies10are utilized in combination. Additionally, other components generally known in the art can be utilized with the log saw assembly10. In some embodiments, a log pusher is utilized to longitudinally locate a product roll or log24along a log axis25of the log saw assembly10.

The log saw clamping assembly18includes an infeed clamp26, an outfeed clamp30, a support mechanism34, and a drive mechanism38. It should be noted that not all components of the log saw clamping assembly18are necessary to practice the invention. The invention can include the use of a single clamp. As described further below, the log saw drives the log saw blade22along a log saw blade path40(FIG. 3). The log saw blade path40is a transverse path between the infeed and outfeed clamps26and30.

As best shown inFIG. 5, the infeed clamp26of the illustrated embodiment includes pivoting clamp paddles42, a cam follower assembly46, and a clamp housing assembly50.FIG. 5illustrates only a single pivoting clamp paddle42which has been inverted for clarity.

The pivoting clamp paddles42each include a pivot shaft54about which the clamp paddles42pivot. The pivot shaft54is supported by the clamp housing assembly50for pivotable rotation of the clamp paddles. Alternatively or in addition, the clamp paddles42can be rotatably connected to the pivot shafts54for the same motion. First and second pivot arms58are connected to the pivot shaft54for rotation relative to the cam follower assembly46. Each pivot arm58includes a cam surface62and a paddle surface66. A paddle70is utilized to contact the log24. The paddle70may include a variety of shapes (e.g., flat, curved, V-shaped, bar member, pole member, other member, and the like) and sizes. In some embodiments, the leading edge and/or the trailing edge of the paddle70is beveled or chamfered to enhance feeding guidance of the log24and to prevent gouging of the log24upon entrance to or exit from the log saw assembly10. The illustrated paddle70includes a contact surface70aand a connection surface70b(FIG. 4). The connection surface70bis connected to the paddle surfaces66of the pivot arms58for movement of the paddle70therewith. In other embodiments, any number of pivot arms58may be utilized to support the paddle (e.g., as few as one, three, or more). In yet other embodiments, the paddle70and the pivot arm58may be integrally formed.

In some embodiments, a counterweight74is connected to the pivot shaft54for rotation therewith. As shown inFIGS. 1 and 4, a counterweight spring78can be employed to connect the counterweight74of one pivoting clamp paddle42to the counterweight74of an adjacent pivoting clamp paddle42.

In some embodiments, shoes or extenders (not shown) are connected to the paddles70for use in the clamping of product rolls or logs having diameters smaller than the diameter of the log24. The interstitial space (FIGS. 6-9) between the log24and the contact surface70aof the paddle70or the extender that is contacting the log24can vary. In some embodiments, the interstitial space has a radial thickness of approximately 0.25 inches when the surface contacting the log is in an open position as discussed further below. The thickness of the extenders can vary to accommodate logs of various diameters. In some embodiments, each extender has a length and a width similar to the length and the width of the paddle70to which the extender is attached. Also, in some embodiments, the extender can include a body construction similar to the illustrated paddles70(in which cases the extenders can define the paddles70or can be connected to the paddles in any suitable manner). In other embodiments, the extender includes a frame portion and a paddle portion. Provision of a frame portion can provide the necessary structural integrity of the extender while reducing the overall weight of the extender when compared to a similarly sized extender having a solid body construction. In some embodiments, weight is added to the counterweights74to account for the additional weight on the paddles70.

The cam follower assembly46can include a cam follower housing86as best shown inFIG. 5. In the illustrated embodiment, the cam follower housing86includes first and second cam follower housing rings86rseparated by cam follower housing spacers86s. In some embodiments, the cam follower housing86is machined from a single piece of material, thereby enhancing the structural integrity of the cam follower housing86and helping to provide proper balance of the cam follower housing86. In other embodiments, components of the cam follower housing86are separately manufactured and connected together in any suitable manner (e.g., welding, bolts, screws, pins, rivets, and other conventional permanent and releasable fasteners, inter-engaging components, and the like). In other embodiments, a simple ring or tubular element of any length can be employed.

A cam follower ring gear90is connected to the cam follower housing86with cam follower ring gear connectors94. In other embodiments, the cam follower ring gear90and the cam follower housing86may be integrally formed. In the illustrated embodiment, six circumferentially spaced cam follower ring gear connectors94are utilized. In other embodiments, the number of connectors94can vary.

In the illustrated embodiment, inner cam followers98and outer cam followers102are rotatably coupled to the cam follower housing86. In some embodiments, the inner cam followers98are a stud type cam follower and the outer cam followers102are an eccentric stud type cam follower, each provided by McGill Manufacturing Company of Valparaiso, Ind. The eccentric stud type cam followers allow for adjustment of the radial position of the outer cam follower102relative to the outer cylindrical surface of cam follower housing ring86rto which the outer cam follower102is attached. This adjustment is useful in equalizing the load shared by each of the outer cam followers102. Adjustment may also be necessary to compensate for wear of the cam follower102or a cam surface on which the cam follower102travels. In other embodiments, other types of inner and/or outer cam followers98and102are utilized.

In some embodiments, axial alignment mounts106are connected to the cam follower housing86to help retain the cam follower housing86in proper axial position with respect to the clamp housing assembly50. The axial alignment mounts106can be located adjacent the inner and outer cam followers98and102as shown inFIG. 5. The axial alignment mounts106extend axially past the inner and outer cam followers98and102. In some embodiments, the axial alignment mounts106are constructed of an ultra high molecular weight polyethylene material, but can be constructed of other material as desired.

With reference toFIG. 5of the illustrated exemplary embodiment, the inner cam followers98and the axial alignment mounts106are coupled to the cam follower housing86radially inward of the outer cam followers102. The outer cam followers102are mounted such that a portion of each outer cam follower102extends radially past the cam follower housing86. In some embodiments, the number of each of the inner and outer cam followers98and102and the axial alignment supports106is equal to the number of pivoting clamp paddles42. In other embodiments, the number of each can vary.

The clamp housing assembly50includes a barrel housing110having elongated apertures112. In some embodiments, the barrel housing110includes six elongated apertures112circumferentially spaced about the barrel housing110. The number of elongated apertures112can be equal to the number of cam follower ring gear connectors94. In other embodiments, the number of each can vary. In some embodiments, one or more cam follower assembly limit stops134are connected to the barrel housing110. The limit stops134can be connected between adjacent elongated apertures112on the outer cylindrical surface of the barrel housing110. In the illustrated embodiment, a single cam follower assembly limit stop134extends to cover a portion of each of two adjacent elongated apertures112. In other embodiments, the shape and configuration of the cam follower assembly limit stops134can vary. The cam follower assembly limit stops134can be constructed of an ultra high molecular weight polyethylene material, although other limit stop materials can be employed as desired.

In some embodiments of the present invention, a first side plate114is connected to a first surface of the barrel housing110and/or a second side plate122is connected to a second surface of the barrel housing110. In such embodiments, a circular recess or groove154(FIG. 5) can be machined in the inner planar surface of each side plate114and122. Where employed, each recess154can be sized substantially similar to the corresponding surfaces of the barrel housing110. The barrel housing110can therefore extend into the circular recess(es)154when the first and/or second side plates114and122are connected to the barrel housing110. In other embodiments, the barrel housing110can be integrally formed or otherwise connected with the side plates114and122.

The first and second side plates114and122can be circular and define an opening142through which the log24passes. In the illustrated embodiment, the perimeter of the opening142is defined by recess portions and flange portions in which are located apertures150. The first and second side plates114and122can also include slot apertures158and access apertures162as desired.

In the illustrated exemplary embodiment, a barrel housing ring gear130is connected to the first side plate114radially outward of the connection between the barrel housing110and the first side plate114. The inner diameter of the barrel housing ring gear130can be substantially equal to the outer diameter of the barrel housing110. The barrel housing ring gear130includes a geared portion130a(FIG. 3) that can be substantially similar to the geared portion of the cam follower ring gear90. Utilization of similar geared portions allows for synchronization of the drive speeds of the cam follower assembly46and the barrel housing assembly50about the log axis25as discussed further below. The barrel housing ring gear130can also include a non-geared portion130b(FIG. 3) that acts to space the barrel housing ring gear130from the first side plate114.

The pivoting clamp paddles42, the cam follower assembly46, and the clamp housing assembly50of the illustrated embodiment are assembled to form a clamp26,30(e.g., the outfeed clamp30). The cam follower assembly46is supported by the clamp housing assembly50for rotation with respect to the clamp housing assembly50. When the cam follower assembly46rotates with respect to the clamp housing50, the pivoting clamp paddles42pivotably rotate to circumferentially engage and disengage the log24. In some embodiments, the pivoting clamp paddles42are spaced circumferentially about the axis25to engage the log24. The operation of the clamp26,30is discussed in greater detail below.

When the clamp26,30is assembled, the pivot shaft54of each pivoting clamp paddle42is captured in a corresponding set of apertures150in the first and second side plates114and122. The apertures150can include bearings that enhance rotation of the pivot shafts54. In some embodiments, the outer surfaces of the pivot arms58are axially spaced by a distance substantially equal to the distance between the inner surfaces of the first and second side plates114and122. Such spacing reduces axial movement of the pivoting clamp paddles42with respect to the clamp housing assembly50. Although the counterweights74can be located on either side of the first and second side plates114,122, the counterweight74of each pivoting clamp paddle42can be connected to the pivot shaft54outboard of side plate114(FIGS. 1 and 4) or of both side plates114,122. Such placement also reduces the axial movement of the pivoting clamp paddles42. In those embodiments of the present invention employing side plates114,122having recess portions as described above, the recess portions of the first and second side plates114and122can be sized to receive a sectional portion of the paddles70. As illustrated inFIG. 3, the distance by which the paddles70extend axially past the first and/or second side plates114and122can vary.

With continued reference to the illustrated exemplary embodiment of the present invention, the cam follower housing86is received radially inboard of the inner cylindrical surface of the barrel housing110. The cam follower ring gear90can be connected to the cam follower housing86in any suitable manner, and in the illustrated embodiment is connected to the cam follower housing86by the cam follower ring gear connectors94. For such connection, the cam follower connectors94extend radially through the elongated apertures112. In the illustrated embodiment, the inner diameter of the cam follower ring gear90is substantially equal to the outer diameter of the barrel housing110. The cam follower ring gear90in this embodiment is disposed axially adjacent the geared portion130aof the barrel housing ring gear130on a first side and the cam follower assembly limit stops134on a second side.

In some embodiments, the inner cylindrical surface of the barrel housing110defines first and second cam surfaces or tracks on which the sets of outer cam followers102are adapted to ride. The outer cam followers102can be adjusted as discussed above so the cam follower assembly46is concentrically spaced with respect to the inner cylindrical surface of the barrel housing110.

The illustrated cam followers98and102rotate about their axes. In other embodiments, the cam followers98and102can be replaced by wear pins, plates, pads, or other moving and non-moving elements. In other embodiments, the cam follower housing86can rotate relative to the barrel housing110by employing a set of bearings or wear pads between the cam follower housing86and barrel housing110. In other embodiments, a single structure may perform the function of each cam follower98and102.

The inner surfaces of the first and second side plates114and122in the illustrated exemplary embodiment prevent axial movement of the cam follower assembly46by limiting axial movement of the axial alignment supports106. If the cam follower assembly46begins to move in an axial direction, the axial alignment supports106contact the respective inner planar surface of an adjacent side plate114,122, which thereby prevents further axial movement in the same direction. To this end, the axial alignment supports106can extend axially beyond the inner and outer cam followers98and102to prevent the cam followers98and102from contacting the respective inner surfaces of the first and second side plates114and122. Such contact could affect the cam action of the cam followers98and102in some embodiments.

In some embodiments, the side plates114and122extend radially past the barrel housing110, the cam follower ring gear90, and the barrel housing ring gear130. Such side plates114and122therefore have a diameter that is larger than the diameter of the barrel housing110, the diameter of the cam follower ring gear90, and the diameter of the barrel housing ring gear130.

Where employed, the slot apertures158are adapted to vent debris to the outside of the clamp26,30. The slot apertures158can be disposed adjacent and radially inward of the connection between the barrel housing110and the side plates114and122. Also where employed, the access apertures162allow an operator to access the components (e.g., the outer cam followers102) of the cam follower assembly46if adjustments are necessary.

As illustrated inFIGS. 2 and 3, the infeed clamp26can be substantially identical to the outfeed clamp30(i.e., the infeed clamp26in the illustrated embodiment is a mirror image of the outfeed clamp30about the log saw path40). Accordingly, like parts of the infeed and outfeed clamps26and30in the illustrated embodiment are indicated with like reference numerals. The only structural difference between the outfeed clamp30and the infeed clamp26of the illustrated exemplary embodiment is the orientation of the pivoting clamp paddles42relative to the clamp housing assembly50. In particular, the pivoting clamp paddles42of the outfeed clamp30are orientated in an opposite direction relative to the clamp housing assembly50compared to the orientation of the pivoting clamp paddles42of the infeed clamp26such that the pivoting clamp paddles42of the infeed and outfeed clamps26and30both pivot in the same direction with respect to the axis25.

Referring toFIGS. 1,2, and3, the frame14supports the support mechanism34and the drive mechanism38. The frame14can have any shape and form suitable for this purpose. By way of example only, the illustrated frame14includes vertically extending plate portions14aand horizontally extending support bars14b. A variety of brackets and braces14ccan be coupled to the plate portions14aand support bars14bas needed.

In the illustrated embodiment, the support mechanism34includes two sets of bottom support rollers34a, two sets of top support rollers34b(not shown inFIG. 2for clarity), and three sets of thrust support rollers34c(some not shown inFIG. 2for clarity). The support mechanism34is adapted to support the infeed and outfeed clamps26and30for rotation about the axis25. Fewer or additional support mechanisms34(in the form of rollers, bearings, and the like) can be employed based at least partially upon the type of frame14used in various embodiments of the present invention, the anticipated loads exerted by the clamps26,30in operation, and other considerations.

With continued reference to the exemplary embodiment of the present invention illustrated in the figures, the bottom support rollers34aare rotatably mounted on a shaft34dfor independent rotation. The shaft34dis connected to the frame14, but can instead be connected to one or more brackets or other structure securing the shaft34dagainst lateral, axial, and vertical movement. The bottom support rollers34acontact the side plates114,122of the clamps26,30, support the clamps26,30, and retain the clamps26,30in desired positions with respect to the frame14. To this end, each top support roller34bcan have any shape capable of performing these functions, and in some cases includes a cylindrical support surface (FIG. 1). The cylindrical surfaces of the first and second side plates114and122of the infeed and outfeed clamps26and30are supported on the cylindrical support surfaces of the bottom support rollers34a.

Any number of bottom support rollers34acan be employed as desired. In the illustrated embodiment for example, each set of bottom support rollers34aincludes a first bottom support roller34athat supports the first side plate114of the infeed clamp26, a second bottom support roller34athat supports the second side plate122of the infeed clamp26and the second side plate122of the outfeed clamp30, and a third support roller34athat supports the first side plate114of the outfeed clamp30. In other embodiments, the configuration of bottom support rollers34acan vary. The bottom support rollers34aprevent the infeed and outfeed clamps26and30from moving vertically downward. The bottom support rollers34acan also act in combination with the top support rollers34bto prevent the infeed and outfeed clamps26and30from moving laterally. In the illustrated embodiment by way of example only, the bottom support rollers34ainclude a diameter of approximately ten inches. In other embodiments, the diameter of the bottom support rollers34acan vary. Additionally, the axial length of the bottom support rollers34acan vary, although in some embodiments (such as the illustrated embodiment) the bottom support rollers34aare spaced to allow for interaction between the drive system38and the infeed and outfeed clamps26and30as will be described in greater detail below.

Where employed, each top support roller34bis rotatably mounted on a shaft34efor independent rotation. The shaft34eis coupled to a bracket14c, but can instead be connected directly to the frame14or to other structure securing the shaft34eagainst lateral, axial, and vertical movement. The top support rollers34bcontact the side plates114,122of the clamps26,30in order to retain the clamps26,30in desired positions with respect to the frame14. To this end, each top support roller34bcan have any shape capable of performing this function, and in some cases includes a grooved support surface (FIG. 3). The grooved support surface of the top support rollers34bare sized to receive surfaces of the first and second side plates114and122of the infeed and outfeed clamps26and30for support thereof.

Any number of top support rollers34bcan be employed as desired. In the illustrated embodiment for example, each set of top support rollers34bincludes a first top support roller34bthat supports the first side plate114of the infeed clamp26, a second top support roller34bthat supports the second side plate122of the infeed clamp26, a third top support roller34bthat supports the second side plate122of the outfeed clamp30, and a fourth support roller34bthat supports the first side plate114of the outfeed clamp30. In other embodiments, the configuration of top support rollers34bcan vary. The top support rollers34acan prevent the infeed and outfeed clamps26and30from moving vertically upward. The top support rollers34bcan also act in combination with the bottom support rollers34ato prevent the infeed and outfeed clamps26and30from moving laterally. The top support rollers34bcan also act in combination with the thrust support rollers34cto prevent the infeed and outfeed clamps26and30from moving axially. In the illustrated embodiment by way of example only, the top support rollers34binclude a diameter of approximately four inches. In other embodiments, the diameter of the top support rollers34bcan vary.

Where employed, each thrust support roller34cis rotatably mounted to the frame14for independent rotation, but can instead be connected to one or more brackets or other structure securing the support roller34cagainst lateral, axial, and vertical movement. To this end, each thrust support roller34ccan have any shape capable of providing such support, and in some cases includes a cylindrical support surface. The outer surfaces of the first and second side plates114and122of the infeed and outfeed clamps26and30are supported by the cylindrical support surfaces of the thrust support rollers34c.

Any number of thrust support rollers34ccan be employed as desired. In the illustrated embodiment for example, each set of thrust support rollers34cincludes a first set of thrust support rollers34cthat supports the outer surface of the first side plate114of the infeed clamp26, a second set of thrust support rollers34cthat supports the outer surface of the second side plate122of the infeed clamp26, a third set of thrust support rollers34cthat supports the outer surface of the second side plate122of the outfeed clamp30, and a fourth set of thrust support rollers34cthat supports the outer surface of the first side plate114of the outfeed clamp30. The thrust support rollers34ccan prevent the infeed and outfeed clamps26and30from moving axially.

The cam follower ring gear90and the barrel housing ring gear130can be rotated in a variety of conventional manners (e.g., chains, belts, and the like). The embodiment of the present invention illustrated in the figures provides an example of a drive mechanism38that can be employed for this purpose. The cam follower assembly46and the clamp housing assembly50are each rotatable about the log axis25. Additionally, the cam follower assembly46is rotatable with respect to the clamp housing assembly50to cause the pivoting clamp paddles42to move circumferentially inward and outward to engage and disengage the log24as will be discussed in greater detail below. As also discussed further below, the direction of circumferential movement of the pivoting clamp paddles42depends on the direction of rotation of the cam follower assembly46with respect to the clamp housing assembly50. In other embodiments, the clamp housing assembly50may be rotatable with respect to the cam follower assembly46.

In the illustrated embodiment, cam follower drive belts38aare drivingly coupled to the cam follower ring gears90of the infeed and outfeed clamps26and30, while barrel housing drive belts38bare drivingly coupled to the barrel housing ring gears130of the infeed and outfeed clamps26and30. In some embodiments, each cam follower drive belt38ais driven by a cam follower gear38cmounted on a cam follower shaft38dfor rotation therewith. A cam follower drive belt tensioner38e(FIG. 1) can be utilized to appropriately tension the cam follower drive belt38afor operation. In some embodiments, each barrel housing drive belt38bis driven by a barrel housing gear38fmounted on a barrel housing shaft38gfor rotation therewith. A barrel housing drive belt tensioner38h(FIG. 1) can be utilized to appropriately tension the barrel housing drive belt38bfor operation.

Any driving device can be employed to power the clamps26,30. By way of example only, a motor (e.g., a fifteen horsepower electric motor)38iis employed in the illustrated embodiment, and is drivingly connected to the barrel housing shaft38gby a timing belt38j(although other conventional driving elements can be employed in alternative embodiments). The timing belt38jis driven by a motor drive gear38kmounted on an output shaft of the motor38i. The timing belt38jdrives the barrel housing shaft38geither directly or indirectly (e.g., via a barrel housing drive gear381mounted on the barrel housing shaft38gas shown in the figures). A timing belt38mdrivably couples the barrel housing shaft38gto the cam follower shaft38din any suitable manner. By way of example only, the timing belt38mcan be driven by a barrel housing drive gear38nand can drive a gear38ocoupled to a differential gear box38p. Tensioners38tand38scan be utilized to appropriately tension the timing belts38jand38mfor operation.

The differential gear box38pallows for a differential between the speeds of the cam follower shaft38dand the barrel housing shaft38g. In other embodiments, the differential gear box38pcan be coupled to the barrel housing shaft38gand the cam follower shaft38dcan be driven by the timing belt38j. In some embodiments, the differential gear box38pincludes an 80:1 trim ratio. A servo motor38qcan be coupled to the differential gear box38pto control the differential between the speeds of the cam follower shaft38dand the barrel housing shaft38g. In some embodiments, actuation of the servo motor38qresults in a speed differential of plus or minus approximately 2-3 revolutions per minute (“RPM”) for the cam follower shaft38dwhen compared to the standard operating speed of the barrel housing shaft38gof approximately 300-400 RPM. As an alternative to a differential gear box38pto provide a speed difference between the shafts38d,38g(controllable or otherwise), any conventional mechanism or assembly for establishing a speed difference between rotating elements can instead be employed. The speed differential of the cam follower shaft38dwhen compared to the barrel housing shaft38gresults in rotation of the cam follower assembly46with respect to the barrel housing50. In some embodiments, a braking mechanism38r(e.g., an air brake) is utilized to slow the rotation of the drive mechanism38.

For operation, the pivoting clamp paddles42include different positions with respect to the log24.FIG. 6illustrates the pivoting clamp paddles42in an open or indexing position with respect to the log24.FIGS. 7 and 8each illustrate the pivoting clamp paddles42in a rotating position with respect to the log24.FIG. 9illustrates the pivoting clamp paddles42in a cutting, sawing, or clamping position with respect to the log24. The position of the pivoting clamp paddles42with respect to the log24is defined by the extent of rotation of the cam follower assembly46with respect to the clamp housing assembly50.

In the illustrated embodiment, the cam follower assembly46is allowed to rotate approximately thirty degrees with respect to the clamp housing assembly50. In other embodiments, this amount of rotation can be larger or smaller as desired. As used herein, degrees of rotation are defined with respect to the direction of operational rotation of the infeed and outfeed clamps26and30illustrated in the figures. The outfeed clamp30as illustrated inFIGS. 6-9includes a counter-clockwise direction of operational rotation as indicated by arrow105. Therefore, the cam follower assembly46and the clamp housing assembly50of the outfeed clamp30can both rotate in a counter-clockwise direction about the axis25during operation of the log saw assembly10.

The clamping action of the invention is provided when the cam follower assembly46rotates with respect to the clamp housing assembly50. As discussed above, movement of the outer cam followers102on the tracks of the barrel housing110in the illustrated embodiment allow for such rotation. With reference toFIGS. 6-9, the cam follower assembly46rotates in a counter-clockwise direction with respect to the clamp housing assembly50when the differential speed between the cam follower assembly46and the clamp housing assembly50is positive. The cam follower assembly46rotates in a clockwise direction with respect to the clamp housing assembly50when the differential speed between the cam follower assembly46and the clamp housing assembly50is negative. The cam follower assembly46does not rotate with respect to the clamp housing assembly50when there is no differential speed between the cam follower assembly46and the clamp housing assembly50.

In the open position, the cam follower assembly46is rotated approximately zero degrees with respect to clamp housing assembly50. In the sawing position, the cam follower assembly46is rotated approximately thirty degrees with respect to the clamp housing assembly50in the illustrated embodiment (although other amounts of rotation can instead be employed, depending at least partially upon the size and shape of the pivot arms58and the amount of radial movement desired for clamping. In the various rotating positions, the cam follower assembly46is rotated with respect to the clamp housing assembly50somewhere between the open position and the sawing position. In some embodiments, the pivoting clamp paddles42are in a rotating position when the cam follower assembly46is rotated between approximately ten and twenty degrees with respect to the clamp housing assembly50. In other embodiments, the positions of the pivoting clamp paddles42can vary.

In the open position, the pivoting clamp paddles42are each retracted, and can be in a fully retracted position in which no further radially outward movement of the clamp paddles42is possible. When the pivoting clamp paddles42are retracted, the connection surfaces70bof the paddles70can rest against the recess portions (where employed) of the first and second side plates114and122. Thus, the interstitial space between the contact surfaces70aof the paddles70and the log24can be the greatest in these positions of the paddles70. As discussed above, extenders can be utilized to radially extend the contacting surface of the pivoting clamp paddles42towards the log24if the interstitial space is too large. Additionally, when the pivoting clamp paddles42are in an open position, in some embodiments the cam follower ring gear connectors94(where employed) are each restricted from movement against the direction of rotation of the infeed and outfeed clamps26and30by the cam follower assembly limit stops134. In the illustrated embodiment for example, the cam follower assembly limit stops134restrict rotation of the cam follower assembly46with respect to the clamp housing assembly50to approximately thirty degrees, although other ranges of movement are possible based at least partially upon the positions of the cam follower assembly limit stops134.

To begin operation of the illustrated log saw assembly10(having infeed and outfeed clamps26,30), a log pusher advances the log24axially into the log saw clamping assembly18while the pivoting clamp paddles42are in the open position. The log24is axially advanced until a portion of the log24extends past the log saw blade path40into the outfeed clamp30. Typically, a small length or “cookie” is cut from the leading edge of the log24to eliminate the ragged edge produced by many rewinding processes.

Once the log24is axially located, the rotation of the infeed and outfeed clamps26and30can be utilized to accelerate the log24from a standstill to the desired rotational speed in a fast and controlled manner. In some cases, the log24can be inserted in the log saw assembly10while the infeed and outfeed clamps26,30are rotating. The drive mechanism38provides rotation to the infeed and outfeed clamps26and30as discussed above. To accelerate the log24, the pivoting clamp paddles42can be moved concentrically inward from the open position toward the axis25and to a rotating position. Concentric movement of the pivoting clamp paddles42can be utilized to center the log24on the axis25.

As discussed above, the pivoting clamp paddles42move from the open position to a rotating position when the differential speed between the cam follower assembly46and the clamp housing assembly50is positive. With reference toFIGS. 6-9for example, counter-clockwise movement of the cam follower assembly46with respect to the clamp housing assembly50results in movement of the inner cam followers98with respect to the cam surfaces62of the pivot arms58in a direction away from the pivot shaft54. This cam action moves the contact surfaces70aconcentrically inward toward the axis25. When the pivoting clamp paddles42are in a rotating position, the cam follower ring gear connectors94are disposed between two adjacent cam follower assembly limit stops134(if employed). Therefore, the cam follower assembly limit stops134do not restrict the above-described movement of the cam follower assembly46with respect to the clamp housing assembly50in the counter-clockwise direction or the clockwise directions.

When the log24has reached a desired rotational speed, the pivoting clamp paddles42can move concentrically inward toward the axis to engage the log24for cutting. As discussed above, the pivoting clamp paddles42move from a rotating position to the sawing position when the differential speed between the cam follower assembly46and the clamp housing assembly50is positive. With reference again toFIGS. 6-9for example, continued counter-clockwise movement of the cam follower assembly46with respect to the clamp housing assembly50results in continued movement of the inner cam followers98with respect to the cam surfaces62of the pivot arms58in a direction away from the pivot shaft54. This cam action moves the contact surfaces70aconcentrically further inward toward the axis25. When the pivoting clamp paddles42are in the sawing position, the cam follower ring gear connectors94are each restricted from movement in the direction of rotation of the infeed and outfeed clamps26and30by the cam follower assembly limit stops134(if employed). Once the sawing position is achieved, the log saw blade22is utilized to saw the portion of the log24through which the log saw blade path40extends.

In some embodiments, the log saw blade22is coupled to a pivoting arm for lowering the log saw blade22into the log24. The log saw blade22cuts through the exterior of the log24first and proceeds radially inward until a portion of the log saw blade22extends through the core24a(FIG. 1) of the log24, or through a center portion of the log in the case of coreless logs. In some embodiments in which logs having cores are cut, the log saw blade22extends through the core24aapproximately 0.25 inches. The log saw blade22can be rotated by a variety of conventional mechanisms or can be rotated by the drive mechanism38. Alternatively, the log24can be “sawn” by a log saw comprising high pressure fluid or solid application, or even by hot wire, torch or laser cutting.

In the illustrated embodiment, the log saw blade22rotates at a higher rate of speed than the infeed and outfeed clamps26and30. In some embodiments, rotation of the log24through at least 170 degrees prevents the log saw blade22from having to travel more than about half the diameter of the log24. In addition, the rotational speed of the log24can define the duration of sawing necessary to saw through the entire section of the log24. This sawing process can more evenly load the log saw blade22and the core of the log24, thereby substantially reducing bias cutting and core crushing problems and increasing product quality. Further, decreased deflection of the log saw blade22under more even lateral loading of the present invention can prolong log saw blade22life. Rotation of the log24with respect to the log saw blade22can also allow for placement of a plurality of thrust support rollers34con the same plane as the log saw blade path40, thereby providing enhanced structural integrity of the log saw clamping assembly18.

Once the “cookie” has been separated from the log24, the pivoting clamp paddles42move concentrically outward away from the axis so the log pusher14can index the log24to the next desired position. The contact surfaces70acan include a low friction surface to facilitate movement of the log24through the infeed and outfeed clamps26and30. Further, as discussed above, the edges of the paddles70can be beveled or chamfered to provide further feeding guidance and to prevent gouging of the log24. In the illustrated embodiment, the log24continues to rotate at approximately 300-400 RPM during the entire sawing and indexing process, although faster or slower speeds are possible. In other embodiments, the rotational speed of the log24is reduced or stopped to axially index the log24through the log saw clamping apparatus18. After sawing, the sawn material can be discharged by the log pusher and then handled in a conventional manner. The log pusher can comprise any number of pushing or pulling mechanisms for placing a log24comprising rolled paper or other material to be sawn in the desired position.

In some embodiments, the counterweight74includes a counterweight pin74aor other extension (FIG. 4) that contacts the pivot arm (e.g., the inner surface of the pivot arm58adjacent the first side plate114in the illustrated embodiment). If the pivoting clamp paddle42begins to pivot inward toward the axis25while the clamp26,30is still in the open position, the counterweight pin74acan be employed to restrict such movement. The counterweights74(acting through pin74aand spring78) bias the pivoting clamp paddles42to the open position when the clamps26and30are in a static or non-rotating mode of operation. This arrangement allows the pivoting clamp paddles42to move between the open and closed positions when the cam follower assembly46is rotated relative to the clamp housing assembly50.

In other embodiments, the log24can be rotated independently of the infeed and outfeed clamps26and30. By way of example only, a plurality of rollers can be utilized to substantially match the rotational speed of the log24to the rotational speed of the infeed and outfeed clamps26and30. Such rollers can be driven by a variety of conventional mechanisms or can be driven by the drive mechanism38.

In some embodiments, a plurality of log saw assemblies10are utilized in combination. The log saw assembly10can be adapted to interface with a second log saw assembly (e.g., employing two log saw assemblies10that are substantially the same). To this end, the barrel housing shaft38gcan include a splined connection100on the outfeed side of the frame14(FIG. 3). The splined connection100can be coupled with a barrel housing shaft of a second log saw assembly having a corresponding splined connection on the infeed side of the frame. When thus coupled, the motor38ican drive the drive mechanism and the corresponding shafts, gears, and belts of the second log saw assembly. The differences between the log saw assembly10and a second connected log saw assembly can include minor alterations to the drive system of the second log saw assembly to ensure the log saw assembly10remains drivingly coupled to the second log saw assembly (e.g., by the addition of a clamp shaft that locks the splined connection100and a hand knob for disengaging the splined connection100). One having ordinary skill in the art will appreciate that the barrel housing shaft38gof the log saw assembly10can be drivably connected to a barrel housing shaft38gof another log saw assembly10in a number of other conventional manners. In embodiments where multiple log saw assemblies are utilized, the axial indexing provided by the log pusher can be adjusted so that the first log saw provides preliminary cuts and the second log saw provides cuts that yield finished products.

In some alternative embodiments of the present invention, the clamp housing assembly50does not rotate, and the cam follower assembly46only rotates with respect to the clamp housing assembly50to open and close the clamps26,30in a manner as described above. Depending at least partially upon the type of saw and blade employed, this arrangement can require the log saw blade22to pass through an entire section of the log24. However, the unique clamping of the present invention still provides advantages over prior art clamps.