Patent Description:
In the process of shipping one or more articles from one location to another, a packer typically places some type of dunnage material in a shipping container, such as a cardboard box, along with the article or articles to be shipped. The dunnage material typically is used to wrap the articles, or to partially or completely fill the empty space or void volume around the articles in the container. By filling the void volume, the dunnage restricts or prevents movement of the articles that might lead to damage during the shipment process. The dunnage also can perform blocking, bracing, or cushioning functions.

Some commonly used dunnage materials are plastic foam peanuts, plastic bubble pack, air bags, and converted paper dunnage material. Unlike most plastic dunnage products, converted paper dunnage material is an ecologically-friendly packing material that is recyclable, biodegradable, and composed of a renewable resource. The stock material is typically provided in sheet form in a bulk supply, such as on a roll or in a fan-folded stack. To produce discrete dunnage products, the conversion process requires a separation step where discrete lengths are separated from the stock material before, after, or during conversion.

<CIT> discloses a device for cutting paper sheets arranged in a stack, comprising a common drive unit for pressing jaws and a cutting blade so that the jaws lead to the blade to fix the stack before inserting the blade into the stack. The stack lies on a support surface. The jaws and the blade move in a vertical direction in vertical guides. The blade moves relative to the jaws against the pressure of a spring element using a pivoting lever.

The present invention provides an improved dunnage cutting mechanism for use with a dunnage conversion machine. The cutting mechanism is compact, easy to use, and uses a pair of opposed cutting blades to produce a discrete length of dunnage product from sheet stock. The opposed cutting blades are brought into contact with one another during a cutting operation of the cutting mechanism to sever or to cut a discrete length of sheet stock from the substantially continuous bulk supply of sheet stock material. At least one of the opposed blades is self-adjustable relative to the other of the opposed blades to account for wear of one or both of the opposed blades over repeated use. The cutting mechanism also includes a blade guard that is commonly movable with one of the opposed blades to restrict movement of the one of the opposed blades independent from the blade guard during the cutting operation.

More particularly, according to a first aspect of the invention, there is provided a cutting mechanism for a dunnage conversion machine as defined by claim <NUM>. Further aspects of the invention are provided by the dependent claims.

The foregoing and other features of the invention are hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawings setting forth in detail one or more illustrative embodiments of the invention. Other objects, advantages and features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the drawings.

Generally, the present invention provides a dunnage conversion machine and method for converting a generally planar, two-dimensional dunnage sheet stock into a relatively increased volume, lower density, three-dimensional dunnage product of a discrete length. Particularly, the dunnage conversion machine is capable of making, and the method provides for making, converted dunnage products having a three-dimensional shape and increased volume per unit of length as compared to the original unexpanded sheet stock. The dunnage products are formed from at least one ply of sheet stock being generally planar and two-dimensional.

Referring now to the drawings, and initially to <FIG>, an exemplary dunnage conversion machine <NUM> is shown schematically and includes a stock supply assembly <NUM>, also herein referred to as a supply assembly <NUM>, having a bulk supply of dunnage sheet stock <NUM>. The sheet stock <NUM> drawn from the bulk supply is also herein referred to as sheet stock material <NUM>.

The bulk supply may be arranged on a stand, a cart, or simply supported adjacent the conversion machine <NUM>. The sheet stock <NUM> of the bulk supply may be of a substantially continuous length, and may be provided either in roll form or as a series of connected, generally rectangular pages in a fan-folded stack. The rolls or stacks can be spliced to successive supplies so as to appear as a never-ending supply to the conversion machine <NUM>.

Multiple rolls or stacks may be used to provide the multiple sheets or webs of stock material for conversion into the three-dimensional dunnage product. Alternatively, a single roll may include multiple plies co-wrapped into the single roll or a single stack may include multiple plies co-folded into the single stack.

Suitable supplies of sheet stock include paper, plastic sheets, or sheets of a combination thereof. The sheet stock also may be laminated or may include a combination of laminated and non-laminated sheet material. An exemplary sheet stock <NUM> for use with the conversion machine <NUM> includes either a single-ply or multi-ply kraft paper. Suitable kraft paper may have various basis weights, such as twenty-pound or forty-pound, for example, and respective plies may have different basis weights. One exemplary sheet stock <NUM> may be a single-ply kraft paper that is recyclable, biodegradable, and composed of a renewable resource.

A conversion assembly <NUM> for receiving the dunnage sheet stock <NUM> from the bulk supply is located downstream of the stock supply assembly <NUM> and converts the sheet stock <NUM> into a converted sheet stock, such as a relatively less dense strip of dunnage <NUM>. The downstream direction is a direction of advancement of stock material through the dunnage conversion machine <NUM>. An upstream direction is the direction opposite the downstream direction of advancement.

An exemplary conversion assembly <NUM> may be configured to randomly crumple the sheet stock <NUM> received therein. For example, the sheet stock material <NUM> may be laterally crumpled across a width of the sheet stock material <NUM> as it is drawn along its longitudinal length in the downstream direction through the dunnage conversion machine <NUM>. In this way, the sheet stock <NUM> may be converted into a three-dimensional strip of dunnage <NUM> having increased volume as compared to the sheet stock <NUM> of the bulk supply.

The converted strip of dunnage <NUM> is drawn through the conversion machine <NUM>, in a downstream direction into and through a cutting mechanism <NUM>. Particularly, the substantially continuous strip of dunnage <NUM> is drawn between opposed blades <NUM> and <NUM> of the cutting mechanism <NUM> for cutting the strip of dunnage <NUM> into dunnage products <NUM> of discrete length. The cutting mechanism <NUM> is located downstream of the conversion assembly <NUM>.

While the stock supply assembly <NUM>, the conversion assembly <NUM>, and the cutting mechanism <NUM> are illustrated as separated elements of the conversion machine <NUM> in <FIG>, one or more of the stock supply assembly <NUM>, the conversion assembly <NUM>, and the cutting mechanism <NUM> may be coupled to, integral with, or separate from one another in other embodiments.

While the cutting mechanism <NUM> is shown downstream of the stock supply assembly <NUM> and the conversion assembly <NUM>, the cutting mechanism <NUM> may be otherwise positioned. For example, the cutting mechanism <NUM> may be positioned downstream of the stock supply assembly <NUM> and upstream of the conversion assembly <NUM>, to cut the unconverted sheet stock <NUM>. In another example, the cutting mechanism <NUM> may be located within the conversion assembly <NUM> such as to cut the sheet stock material during conversion.

As used herein, the term sheet stock refers to material drawn from the bulk supply. The term sheet stock may refer to material that is converted, fully or partially, or to non-converted material. Generally, the cutting mechanism <NUM> is provided for cutting the sheet stock, and the state of the sheet stock being cut depends on the location of the cutting mechanism <NUM> relative to the conversion assembly <NUM>.

Turning now to <FIG>, a cutting mechanism <NUM> is shown for use with a dunnage conversion machine, such as with the dunnage conversion machine <NUM> of <FIG>. The cutting mechanism <NUM> includes a frame <NUM> and a set of opposed cutting blades <NUM>. The opposed cutting blades <NUM> include a primary blade <NUM> and a secondary blade <NUM>. A blade guard <NUM> is provided to restrict completion of a cutting operation of the cutting mechanism <NUM> under predetermined conditions, as will be described herein.

The depicted frame <NUM> includes a base <NUM> fixed to a stationary surface, such as a frame of the conversion machine, for example. The frame <NUM> may be secured in place by way of fasteners or other means. The frame <NUM> is configured, such as via guiding members <NUM>, for guiding one or more of the primary blade <NUM> and the secondary blade <NUM> as they move relative to one another.

At least one guiding member <NUM>, and as illustrated two opposed guiding members <NUM>, extend upwardly from the base <NUM>. The guiding members <NUM> guide movement of at least one of the blades of the set of opposed cutting blades <NUM>. In the depicted embodiment, the guiding members <NUM> guide the primary blade <NUM> toward the secondary blade <NUM> and toward a path of the sheet material between the primary blade <NUM> and the secondary blade <NUM>.

The guiding members <NUM> are coupled to the base <NUM>, such as by fasteners <NUM>, for example nuts and bolts. Other coupling means may be suitable, or one or more of the guiding members <NUM> may be integral with the base <NUM>. The depicted guiding members <NUM> are cylindrical rods, though other suitable shapes may be used in other embodiments. Any suitable number of guiding members, one or more, may be used.

Additionally, terms of direction, such as upwardly, are relative terms, and components of the cutting mechanism <NUM> may be differently oriented in other embodiments. Coupling may refer to direct coupling of two components together or indirect coupling using an intermediary component to couple two components together.

A stop member <NUM> is fixed to a distal end <NUM> of the guiding members <NUM>, opposite a proximal end <NUM> of the guiding members <NUM> coupled to the base <NUM>. The stop member <NUM> limits upward movement of the primary blade <NUM> in a direction away from the secondary blade <NUM>. Fasteners <NUM>, such as nuts and bolts, may be used to couple the stop member <NUM> to the guiding members <NUM>. While the illustrated stop member <NUM> is shown as a plate receiving the guiding members <NUM> through openings in the stop member <NUM>, other constructions may be suitable. For example, one or more of the stop member <NUM>, the guiding members <NUM>, and the base <NUM> may be integral with one another.

While the frame <NUM> is shown including a particular construction in the depicted embodiment of <FIG>, it will be understood that other constructions may be suitable. Generally, the frame <NUM> is configured to support each of the primary blade <NUM> and the secondary blade <NUM> for movement relative to one another and relative to a path of the sheet material between the opposed cutting blades <NUM>. Numerous other constructions providing adequate support and guidance for the blades <NUM> are conceivable.

Turning now to details of the opposed cutting blades <NUM>, a driven assembly <NUM> includes the primary blade <NUM>, which is a driven blade <NUM> that is supported relative to the frame <NUM>, for movement towards the secondary blade <NUM>, via a driven carriage <NUM> of the driven assembly <NUM>. The driven carriage <NUM> is received on the guiding members <NUM> and may be of any suitable shape. The driven blade <NUM> is attached to the driven carriage <NUM>, such as via suitable fasteners <NUM>. While the illustrated embodiment shows the guiding members <NUM> extending through respective cavities in the driven carriage <NUM>, the driven carriage <NUM> may be otherwise slidably coupled to the guiding members <NUM> in other embodiments.

The driven blade <NUM> is supported for being driven across a path of the sheet stock between the driven blade <NUM> and the secondary blade <NUM>, which may be herein referred to as a sheet stock path <NUM>. In this way, the sheet stock, such as a converted strip of dunnage output from a conversion assembly is separated into discrete lengths.

The driven blade <NUM> is supported by the guiding members <NUM> for movement towards the secondary blade <NUM>, such as linear translation towards the secondary blade <NUM> and towards the strip path <NUM>. For example, the driven blade <NUM> acts as a guillotine with respect to the respective sheet material drawn through the cutting mechanism <NUM>. While the driven blade <NUM> is shown and described as being linearly translatable, the driven blade <NUM> could be pivotably moved into engagement/ or contact with the secondary blade <NUM> in other embodiments.

The driven blade <NUM> may be driven manually, such as via an operator applying force to a lever (not shown), for example attached to the driven carriage <NUM>. Alternatively, the driven blade <NUM> may be linearly translated by other suitable means, such as a linear actuator, pneumatics, hydraulics, etc. For example, an actuation pedal may be pressed by an operator's foot, causing an electromechanical linear actuator to move the driven blade <NUM> towards the secondary blade <NUM>.

In some embodiments, the driven blade <NUM> may be resiliently biased, such as linearly resiliently biased away from the secondary blade <NUM>. For example, a biasing element <NUM> (<FIG>), such as a spring, may be coupled between the driven carriage <NUM> and one of the guiding elements <NUM> to enable automatic return of the driven blade <NUM> to its default position. One or more biasing elements <NUM> may be included, and in some embodiments, the biasing element <NUM> may be omitted.

The driven blade <NUM> has a leading driven cutting edge <NUM> for being driven along the driven path <NUM> to engage a respective cutting edge of the secondary blade <NUM>, to cut the sheet material. The driven cutting edge <NUM> may be a linear edge, as shown. In other embodiments, the driven cutting edge <NUM> may be differently shaped.

The driven cutting edge <NUM> is aligned at an angle that is other than orthogonal to the longitudinal direction of translation of the driven blade <NUM> along the guiding members <NUM>. The driven cutting edge <NUM> is also disposed at a fixed angle relative to the secondary blade <NUM>, and relative to a plane of movement of the respective cutting edge of the secondary blade <NUM>.

A biased assembly <NUM> includes the secondary blade <NUM>, which is a biased blade <NUM> that is supported relative to the frame <NUM>, for movement into and through a movement path of the driven blade <NUM>, via a biased carriage <NUM> of the biased assembly <NUM>. The biased blade <NUM> is attached to the biased carriage <NUM>, such as via suitable fasteners <NUM>.

The biased carriage <NUM> is coupled, such as pivotably coupled, to the frame <NUM>, and may be of any suitable shape. In the illustrated embodiment, a suitable fastener <NUM>, such as a pin, extends between the biased carriage <NUM> and the base <NUM> of the frame <NUM>, defining a pivot axis <NUM> of the biased blade <NUM>. The pivot axis <NUM> is disposed near a lateral end <NUM> of the biased blade <NUM>, opposite a lateral end <NUM>, and outside of a path <NUM> of the sheet stock material between the opposed blades <NUM>.

In other embodiments, a different fastener or a slot a key arrangement, for example, may allow for pivotable coupling of the biased blade <NUM> relative to the frame <NUM>. In some embodiments, the pivot axis <NUM> may be disposed intermediately between opposed lateral ends <NUM> and <NUM> of the biased blade <NUM>, rather than near the lateral end <NUM>. In some embodiments, the pivot axis may be a moving pivot axis, such as a translating pivot axis.

Through movement about the pivot axis <NUM>, the biased blade <NUM> is resiliently biased towards the driven blade <NUM> and against movement away from the driven blade <NUM>. The biased blade <NUM> is resiliently biased via at least one biasing member <NUM> towards, and preferably across, a movement path of the driven blade <NUM>, which maybe herein referred to as a driven path <NUM>. As shown, two biasing members <NUM> resiliently urge the biased blade <NUM> towards the driven path <NUM>. The biasing members <NUM>, such as springs, are supported at least partially by the base <NUM>, and may be coupled to the base <NUM> or to the biased carriage <NUM> via suitable fasteners <NUM>.

The biased blade <NUM> has a leading biased cutting edge <NUM> for engaging the driven cutting edge <NUM> of the driven blade <NUM>. The biased cutting edge <NUM> is a linear edge, though may be differently shaped in other embodiments. The biased cutting edge <NUM> is generally movable in a direction transverse a direction of translation of the driven cutting edge <NUM> of the driven blade <NUM>.

Turning now to <FIG>, the cutting mechanism <NUM> is shown in various stages of use to further illustrate relative movement of the opposed blades <NUM>. <FIG> show front views taken through the cross-section A-A of <FIG>. <FIG> show schematic top-view-illustrations of the blades <NUM> and <NUM>. In <FIG>, the driven blade <NUM> translates into the page towards biased blade <NUM>.

In use, the driven blade <NUM>, and particularly the driven cutting edge <NUM>, is movable between a ready position shown in <FIG> and <FIG> and a cut position shown in <FIG> and <FIG>. The driven cutting edge <NUM> also moves through an intermediate position shown in <FIG> and <FIG>, disposed between the ready position and the cut position of the driven cutting edge <NUM>.

In the ready position of the driven cutting edge <NUM> (<FIG> and <FIG>), the biased cutting edge <NUM> is biased across a movement path of the driven cutting edge <NUM>, such as across the driven path <NUM>. This is because via the biasing members <NUM>, absent contact with the driven cutting edge <NUM>, the biased cutting edge <NUM> is aligned at a bias to the driven cutting edge <NUM> of the driven blade <NUM>.

Additionally, at the ready position of the driven cutting edge <NUM>, the driven cutting edge <NUM> and the biased cutting edge <NUM> are not in contact. In some embodiments, via alignment adjustments of one or both of the biased blade <NUM> and the driven blade <NUM>, the blades <NUM> and <NUM> may already be in contact at a ready position of the driven blade <NUM> in other embodiments.

As the driven cutting edge <NUM> is translated into its intermediate position (<FIG> and <FIG>) the driven cutting edge <NUM> and the biased cutting edge <NUM> come into contact or engagement with one another. Contact of the driven blade <NUM> with the biased blade <NUM> effects movement of the biased blade <NUM> (<FIG> and <FIG>). The advancing driven blade <NUM> causes the biased blade <NUM> to pivot about the pivot axis <NUM> against a biasing force of the biasing members <NUM>, and in a direction of movement away from the driven blade <NUM>, such as out of the driven path <NUM>.

The driven cutting edge <NUM> and the biased cutting edge <NUM> engage at a contact point, also herein referred to as a shear point <NUM> (<FIG>). The shear point traverses lengths of both of the driven cutting edge <NUM> and the biased cutting edge <NUM>, as the driven blade <NUM> moves the biased blade <NUM> against its direction of bias away from the driven blade <NUM>. The unique arrangement of the driven blade <NUM> and the biased blade <NUM> provides a scissor-like cutting or shearing of the sheet stock material drawable between the opposed blades <NUM>.

Via the biasing of the secondary or biased blade <NUM>, change in relative alignment of the opposed cutting edges <NUM> and <NUM>, due to wear of one or both of the opposed cutting edges <NUM> and <NUM>, is accounted for over repeated use. As a result, the cutting mechanism <NUM> generally requires less maintenance, such as replacement of blades. Realignment of one or both of the opposed blades <NUM> and <NUM> is minimized, such as when a clean cut is not being made through the sheet stock material. In some embodiments, either of the primary blade <NUM> or the secondary blade <NUM> could be a driven blade with the other of the blades being a biased blade.

Referring now to <FIG>, the blade guard <NUM> will be described in detail. The blade guard <NUM> is generally configured to be coupled between the frame <NUM> and the driven blade <NUM>. Via this coupling, the blade guard <NUM> is configured for common movement with the driven blade <NUM> during at least part of the translation of the driven blade <NUM> between its ready position (<FIG> and <FIG>) and its cut position (<FIG> and <FIG>). Likewise, via this coupling, the blade guard <NUM> is also configured for independent movement separate from the driven blade <NUM> during another part of the stroke of the driven blade <NUM>.

The blade guard <NUM> projects along the driven blade <NUM> in a longitudinal direction between an upper edge <NUM> and a lower edge <NUM>, opposite the upper edge <NUM>. The blade guard <NUM> also projects in a lateral direction between opposed lateral sides <NUM> and <NUM>. The upper edge <NUM>, lower edge <NUM> and opposed lateral sides <NUM> and <NUM> define an outer periphery <NUM> of the blade guard.

The movement of the blade guard <NUM> and the driven blade <NUM> are coordinated through key and slot connections. Generally, the cutting mechanism <NUM> includes a pair of opposed laterally-spaced first slot and key arrangements <NUM> and a pair of opposed laterally-spaced second slot and key arrangements <NUM>. In other embodiments, one or more of either of the first slot and key arrangement <NUM> and the second slot and key arrangement <NUM> may be used. While the blade guard <NUM> is shown as including the slots, the blade guard <NUM> may include the keys in other embodiments.

The first slot and key arrangement <NUM> slidably couples the blade guard <NUM> to the frame <NUM>. The blade guard <NUM> includes a slot <NUM> that guides movement of the blade guard <NUM> independent from and relative to the frame <NUM>. A key <NUM>, such as a fastener <NUM> or other protrusion, is coupled to the frame <NUM>, for example via threading. The fastener <NUM> is coupled to the stop member <NUM>, but may be coupled to another suitable location of the frame <NUM> in other embodiments. A washer <NUM> may be disposed between a head <NUM> of the fastener <NUM> and the blade guard <NUM>, to enable efficient sliding of the blade guard <NUM> relative to the frame <NUM>.

The slot <NUM> is an S-shaped slot having an upper S-portion <NUM> and a lower S-portion <NUM> extending generally parallel to the direction of movement of the driven blade <NUM>. An S-transition region <NUM> of the S-shaped slot <NUM> is disposed between the upper S-portion <NUM> and the lower S-portion <NUM>. The upper S-portion <NUM> and the lower S-portion <NUM> are laterally offset, such that movement of the key through the transition portion causes the blade guard <NUM> to laterally shift relative to the frame <NUM>.

The shift is in a direction <NUM> transverse a direction of common movement with the driven blade <NUM>, which is along the driven path <NUM>. The transverse shifting direction <NUM> is illustrated as orthogonal the driven path <NUM>, though may be otherwise aligned in other embodiments, such as due to alternative slot constructions.

The second slot and key arrangement <NUM> slidably couples the blade guard <NUM> to the driven assembly <NUM>, generally. More particularly, the blade guard <NUM> is coupled to the driven blade <NUM> via the driven carriage <NUM>, and the blade guard includes a slot <NUM> that guides both common and independent movement of the blade guard relative to the driven blade <NUM>. A key <NUM>, such as a fastener <NUM> or other protrusion, is coupled to the driven assembly <NUM>, for example via threading. The fastener <NUM> is coupled to the driven carriage <NUM>, but may be coupled to another suitable location of the driven assembly <NUM> in other embodiments. A washer <NUM> may be disposed between a head <NUM> of the fastener <NUM> and the blade guard <NUM>, to enable efficient sliding of the blade guard <NUM> relative to the frame <NUM>.

The slot <NUM> is an inverted L-shaped slot, having a relatively longer L-portion <NUM> extending along a direction parallel to the translation direction of the driven blade <NUM>. The slot <NUM> also has a relatively shorter L-portion <NUM> aligned transverse the relatively longer L-portion <NUM> and transverse the driven path <NUM>, such as orthogonal to the relatively longer L-portion <NUM> and orthogonal to the driven path <NUM>. Generally, when the blade guard <NUM> is caused to transversely shift due to movement of the blade guard <NUM> related to the S-shaped slot <NUM>, the fastener <NUM> transitions from the relatively shorter L-portion <NUM> to a relatively longer L-portion <NUM>.

Turning next to <FIG>, the cutting mechanism <NUM> including the blade guard <NUM> is shown in various stages of use to further illustrate relative movement of the blade guard <NUM> and the driven blade <NUM>. The blade guard <NUM> moves between an engaged position (<FIG>) and a disengaged position (<FIG> and <FIG>).

With respect to the driven blade <NUM>, the blade guard <NUM> moves between an engaged position, where the blade guard <NUM> is commonly movable with the driven blade <NUM>, to a disengaged position, where the driven blade <NUM> translates separately from the blade guard <NUM>. The outer periphery <NUM> of the blade guard <NUM> projects beyond the driven blade <NUM>, and beyond the driven cutting edge <NUM> when the blade guard <NUM> is in the engaged position.

Thus common movement of the blade guard <NUM> with the driven blade <NUM> restricts cutting of the sheet stock material and engagement of the driven cutting edge <NUM> with the biased cutting edge <NUM> while the blade guard <NUM> is in the engaged position.

Specifically, the blade guard <NUM> is located to at least partially cover, and in the depicted embodiment to fully project beyond, the driven cutting edge <NUM> until the driven cutting edge <NUM> of the driven blade <NUM> is within a predetermined distance of the biased cutting edge <NUM> of the biased blade <NUM>. The predetermined distance may be in the range of about <NUM> to about <NUM>, and preferably may be less than about <NUM>.

Looking to <FIG>, when the driven blade <NUM> is in the ready position, the blade guard <NUM> is in the engaged position. The outer periphery <NUM> of the blade guard <NUM> projects beyond the driven cutting edge <NUM>, such that the lower edge <NUM> of the blade guard <NUM> is nearer the biased blade <NUM> than the driven blade <NUM> is with respect to the biased blade <NUM>.

In the engaged position of the glade guard <NUM>, the fastener <NUM> is in the lower S-portion <NUM> of the S-shaped slot <NUM>, and the fastener <NUM> is in the relatively shorter L-portion <NUM> of the L-shaped slot <NUM>. Because the fastener <NUM> is coupled in the relatively shorter L-portion <NUM> of the L-shaped slot <NUM>, the blade guard <NUM> translates along with the driven blade <NUM> as the driven blade <NUM> is translated in the driven direction <NUM>. Accordingly, the L-shaped slot <NUM> is shaped to maintain the common movement of the blade guard <NUM> and the driven blade <NUM> during at least part of the cutting operation.

As the blade guard <NUM> moves from the engaged position of <FIG> to the disengaged position shown in both <FIG> and <FIG>, the fastener <NUM> moves through the lower S-portion <NUM> of the S-shaped slot <NUM>, towards the upper S-portion <NUM>. As the driven blade <NUM> continues to drive the blade guard <NUM>, the fastener <NUM> continues towards the S-transition region <NUM> of the S-shaped slot <NUM>, between the lower S-portion <NUM> and the upper S-portion <NUM>.

Looking next <FIG>, the driven blade <NUM> is driven into the intermediate position. When the fastener <NUM> is moved into the S-transition region <NUM> of the S-shaped slot <NUM>, the blade guard <NUM> is caused to transversely shift along the shifting direction <NUM> to its disengaged position.

Consequently, when the blade guard <NUM> shifts relative to the frame <NUM>, the fastener <NUM> moves relative to the blade guard <NUM> from the relatively shorter L-portion <NUM> of the L-shaped slot <NUM> to the relatively longer L-portion <NUM>. Once the fastener <NUM> transitions to the relatively longer L-portion <NUM>, the driven blade <NUM> is enabled to move separately from the blade guard and vice versa.

In the initial disengaged position of the blade guard <NUM> of <FIG>, the lower edge <NUM> of the blade guard <NUM> is near but not yet abutting the biased assembly <NUM>. Alternative slot configurations may change this positioning in other embodiments.

Looking last to <FIG>, in the latter disengaged position of the blade guard <NUM>, the lower edge <NUM> of the blade guard is now abutting the biased assembly <NUM> and projects beyond the outer periphery <NUM> of the blade guard <NUM>. The fastener <NUM> travels along the relatively longer L-portion <NUM> of the L-shaped slot <NUM> such that the driven blade <NUM> to which the fastener <NUM> is coupled may reach the cut position.

In the illustrated embodiment, the biasing element <NUM> (<FIG>) may cause the driven blade <NUM> to be returned to the ready position, in turn shifting the blade guard <NUM> along a reverse shifting direction (opposite the shifting direction <NUM>) and into common movement with the driven blade <NUM> as the driven blade <NUM> returns from the cut position, through the driven blade's intermediate position to the ready position. Likewise, as the driven blade <NUM> is returned to the ready position, the biased blade <NUM> may be spring-biased back into the driven path <NUM> via the biasing members <NUM>.

In one summary, the present invention provides a cutting mechanism <NUM>, <NUM> for a dunnage conversion machine <NUM> that selectively cuts dunnage sheet stock drawable through the cutting mechanism <NUM>, <NUM>. The cutting mechanism <NUM>, <NUM> includes a frame <NUM>, a driven cutting means <NUM>, <NUM> supported relative to the frame <NUM>, and a self-adjustable cutting means <NUM>, <NUM> also supported relative to the frame <NUM>. The self-adjustable cutting means <NUM>, <NUM> is arranged to self-adjust its position relative to the driven cutting means <NUM>, <NUM> to account for wear of at least one of the driven cutting means <NUM>, <NUM> and the self-adjustable cutting means <NUM>, <NUM>. The driven cutting means <NUM>, <NUM> and the self-adjustable cutting means <NUM>, <NUM> are engageable with one another to cut the sheet stock drawable between the driven cutting means <NUM>, <NUM> and the self-adjustable cutting means <NUM>, <NUM>. A guarding means <NUM> is arranged to project beyond a driven cutting edge <NUM> of the driven cutting means <NUM>, <NUM> to restrict movement of the driven cutting edge <NUM> beyond an outer periphery <NUM> of the guarding means <NUM> until the driven cutting edge <NUM> is within a predetermined distance from a cutting edge <NUM> of the self-adjustable cutting means <NUM>, <NUM>.

Claim 1:
A cutting mechanism (<NUM>) for a dunnage conversion machine (<NUM>) that selectively cuts dunnage sheet stock drawable through the cutting mechanism (<NUM>), the cutting mechanism (<NUM>) comprising:
a frame (<NUM>) supporting opposed blades (<NUM>) for cutting the sheet stock;
the opposed blades (<NUM>) including a driven blade (<NUM>) having a driven cutting edge (<NUM>) and a secondary blade (<NUM>) having a secondary cutting edge (<NUM>) each supported relative to the frame (<NUM>) and defining a path therebetween along which the sheet stock to be cut may be passed, the driven blade (<NUM>) being supported relative to the frame (<NUM>) for linear translation towards the secondary blade (<NUM>) to cut the sheet stock;
a blade guard (<NUM>) coupled between the frame (<NUM>) and the driven blade (<NUM>), the blade guard (<NUM>) configured to be commonly movable with the driven blade (<NUM>) between an engaged position of the blade guard (<NUM>) where the blade guard (<NUM>) is commonly movable with the driven blade (<NUM>) and a disengaged position of the blade guard (<NUM>) where the driven blade (<NUM>) translates independently of the blade guard (<NUM>); and
a slot and key arrangement (<NUM>, <NUM>) for guiding movement of the blade guard (<NUM>) and the driven blade (<NUM>) relative to one another, one of the blade guard (<NUM>) and the driven blade (<NUM>) including the key (<NUM>, <NUM>) of the arrangement, and the other of the blade guard (<NUM>) and the driven blade (<NUM>) including the slot (<NUM>, <NUM>) of the arrangement, where the slot (<NUM>) is shaped to maintain common movement of the blade guard (<NUM>) and the driven blade (<NUM>) until the blade guard (<NUM>) is in the disengaged position, and thereafter to allow movement of the driven blade (<NUM>) independent from the blade guard (<NUM>);
such that the blade guard (<NUM>) restricts cutting of the sheet stock and restricts independent movement of the driven blade (<NUM>) separate from the blade guard (<NUM>) until the blade guard (<NUM>) is moved to the disengaged position, the blade guard (<NUM>) projecting beyond the driven cutting edge (<NUM>) of the driven blade (<NUM>) and restricting movement of the driven cutting edge (<NUM>) beyond an outer periphery of the blade guard (<NUM>) until the driven cutting edge (<NUM>) is within a predetermined distance from the secondary cutting edge (<NUM>) of the secondary blade (<NUM>).