EP1197321A2

EP1197321A2 - Cushioning conversion machine and method with stock roll brake

Info

Publication number: EP1197321A2
Application number: EP01307872A
Authority: EP
Inventors: Kurt Kung; Dieter Schwarz
Original assignee: Ranpak Corp
Current assignee: Ranpak Corp
Priority date: 2000-09-14
Filing date: 2001-09-14
Publication date: 2002-04-17
Also published as: EP1197321A3

Abstract

A cushioning conversion machine and method for converting sheet stock material into a three dimensional strip of cushioning are disclosed. The conversion machine includes a conversion assembly and a stock supply assembly. The conversion assembly draws sheet stock material from a stock supply roll whereby the stock supply roll is rotated, and converts the stock material into a three dimensional strip of cushioning. The stock supply assembly supports the stock supply roll (11) and includes a braking assembly (72) movable between a brake engaged position and a brake disengaged position. In the brake engaged position, a braking force is imparted to the stock supply roll to prevent the stok supply roll from rotating. In the brake disengaged position, the braking force is removed from the stock supply roll thereby permitting the stock supply roll to rotate. The braking assembly is biased to the brake engaged position by a biasing member and is urged to the brake disengaged position by a force overcoming the bias.

Description

Field of the Invention

The present invention relates to a cushioning conversion machine and method and, more particularly, to a stock roll brake for automatically stopping a stock roll from which stock material is drawn to be converted by the conversion machine.

Background

Cushioning conversion machines known in the art have used a freely rotating stock supply roll from which sheet stock material to be converted is drawn. The stock supply roll, which may comprise single or multi-ply stock material, is typically mounted in an axial configuration or a cradle configuration. In an axially mounted configuration, the stock supply roll is mounted to a spindle which is journalled at its opposite ends. In a cradle mounted configuration, the stock supply roll is supported by a plurality of idler support rollers which are arranged to support the stock supply roll from its underneath and to rotate with the stock supply roll as stock material is drawn therefrom.
Stock material from the stock supply roll is advanced through the conversion machine by means of the same mechanism that advances the material through the forming portion of the machine. Specifically, a pair of gears that have performed a connecting operation have been used to advance the material being converted. These gears stop and start their rotation during the conversion process, and this results in the need to accelerate the stock supply roll every time the gears start, with resulting changes in the tension of the stock material being fed through the conversion machine. These changes in the tension of the material can affect the quality of the dunnage product being produced.
Also, when the conversion process is stopped, the rotational inertia of the stock supply roll, whether of an axially mounted configuration or a cradle mounted configuration, can cause the stock roll to overrun and form a loose loop of material at the supply end of the conversion machine. When the conversion process is resumed, initially the stock material will be at a relatively low tension until the loose loop of material is taken up, at which point the tension on the stock material will rapidly increase, almost instantaneously, to a relatively high level until the stock roll accelerates to match the feed rate through the machine. This quick change in tension can cause the material to tear, as well as degrade the quality of the dunnage product being produced.
Several known techniques have been developed in an effort to reduce the effects of these problems. For example, in the case of an axially mounted stock supply roll a brake has been employed to place a continuous drag on the stock roll. The brake may comprise, for example, a roller mounted to a swing arm which is pivotally secured to support structure of the conversion machine, such as is disclosed in application Serial No. 09/217,245, which is owned by the assignee of the present invention and which is hereby incorporated herein by reference. The spring pulls the roller against the surface of the stock roll to provide a continuous and preferably constant drag thereon. The drag on the stock roll prevents or at least reduces overrun in the stock roll. The drag load is decreased by virtue of a decrease in the tension of the spring as the stock roll is unwound and diminishes in diameter. This may be desirable since as the size of and, accordingly, the inertia in the stock roll decreases, the amount of brake load necessary to prevent its overrun correspondingly decreases.
In the case of the cradle mounted configuration, a roller rides on the top side of the stock supply roll transverse to the path of the stock material. The roller is supported at its ends by swing arms which are pivotally secured to support structure of the conversion machine. The roller is gravity driven into engagement with the perimeter of the stock supply roll to provide a continuous drag on the stock roll, preventing or at least reducing overrun in the stock roll.
Although the foregoing techniques have proven satisfactory, the applicants of the present invention recognized a need for a mechanism which would prevent or at least reduce the likelihood of the occurrence of overrun in the stock supply roll by applying a brake load to the stock supply roll when it is desired to stop the stock roll, for example when a conversion process is completed, and to remove the brake load when it is desired to allow the stock roll to rotate, for example upon initiation of or during a conversion process.

Summary

The present invention provides a braking assembly for cushioning conversion machines and methods that automatically imparts and removes a braking force to a stock supply roll based on whether stock material is being drawn from the stock supply roll.
According to one aspect of the invention, there is provided a cushioning conversion machine including a conversion assembly and a stock supply assembly. The conversion assembly draws sheet stock material from a stock supply roll whereby the stock supply roll is rotated, and converts the stock material into a three dimensional strip of cushioning material. The stock supply assembly supports the stock supply roll and includes a braking assembly movable between a brake engaged position and a brake disengaged position. In the brake engaged position, a braking force is imparted to the stock supply roll to prevent the stock supply roll from rotating. In the brake disengaged position, the braking force is removed from the stock supply roll thereby permitting the stock supply roll to rotate. The braking assembly is biased to the brake engaged position by a biasing member and is urged to the brake disengaged position by a force overcoming the bias.
In one preferred embodiment of the invention, the force overcoming the bias of the biasing member is related to tension generated in the stock material between the stock supply roll and the conversion assembly.
In another preferred embodiment of the invention, the stock supply assembly further includes a dancer device and the braking assembly includes a braking rocker arm. The dancer device moves the braking rocker arm between the brake engaged position and the brake disengaged position based on changes in tension in the stock material between the stock supply roll and the conversion assembly. As is preferred, the biasing member is positioned to maintain the braking rocker arm and the dancer device in coacting relationship with each other as stock material is drawn by the conversion assembly. The biasing member, which preferably comprises a tension spring, has opposite end portions wherein one end is connected to the braking rocker arm and the other end is connected to the dancer device. The dancer device is rotatable about a dancer pivot axis and the biasing member rotationally biases the dancer device about the dancer pivot axis. A preferred dancer device includes a dancer member which is radially offset from the dancer pivot axis and is positioned so that sheet stock material drawn from the stock supply roll is trained about an arcuate portion of the dancer member. In this way, when the sheet stock material is drawn from the stock supply roll, the load on the dancer member is substantially countered by the rotational bias in the dancer device, thereby helping to maintain a greater uniformity of tension in the sheet stock material. The braking rocker arm is preferably rotatable about a brake pivot axis and the biasing member rotationally biases the braking rocker arm about the brake pivot axis. Stops may be included to limit rotational movement of the dancer device or the braking rocker arm.
In yet another preferred embodiment of the invention, the stock supply assembly includes one or more rotatable roll support members that extend transversely to the path of the stock material and engage an outer periphery of the stock supply roll. When the braking assembly is in the brake engaged position the braking force is applied to at least one of the rotatable roll support members to prevent the stock supply roll from rotating. A pair of stock roll guide members, preferably in the form of rollers, are preferably disposed at opposite ends of the stock supply roll for preventing lateral shifting of the stock supply roll on the rotatable roll support members.
In still another embodiment of the invention, the stock supply roll is mounted to a spindle journalled at its opposite ends, the spindle having a drum fixedly mounted to at least one of its ends. According to this embodiment, when the braking assembly is in the brake engaged position the braking force is applied to the drum to prevent the stock supply roll from rotating.
According to still another aspect of the invention, there is provided a cushioning conversion machine comprising a conversion assembly and a stock supply assembly. The stock supply assembly includes a dancer device for helping to maintain a greater uniformity of tension in the stock material as stock material is drawn from the stock supply roll. The dancer device includes a brake member which automatically imparts a braking force to the stock supply roll when stock material is not being drawn from the stock supply roll to prevent the stock supply roll from rotating.
In an embodiment of the invention, the brake member automatically removes the braking force from the stock supply roll when stock material is being drawn from the stock supply roll to permit the stock supply roll to rotate. A biasing member may be used to bias the brake member to impart the braking force.
According to another aspect of the invention, there is provided a cushioning conversion machine wherein the braking assembly is operative to move between the brake engaged position and the brake disengaged position based on the tension in the stock material being drawn by the conversion assembly.
In a preferred embodiment of the invention, the stock supply assembly includes a dancer device in cooperative relationship with the braking assembly. The dancer device is operative to move the braking assembly to the brake disengaged position during a conversion process and to move the braking assembly to the brake engaged position upon completion of a conversion process. Preferably, the movement of the braking assembly is provided by a biasing member which biases the dancer device relative to the braking assembly.
In another preferred embodiment of the invention, the stock supply assembly includes a dancer device which moves in response to changes in the tension of the stock material and the braking assembly is engaged or disengaged based on the movement in the dancer device. A controller may be used to control the braking assembly and a limit switch may be provided to sense the movement in the dancer device and send a signal to the controller to engage or disengage the braking assembly. The limit switch is preferably positioned relative to the dancer device to sense when the dancer device moves due to a change in the tension of the stock material.
In yet another aspect of the invention, there is provided a cushioning conversion machine including a conversion assembly, a stock supply assembly and a controller for controlling the braking assembly of the stock supply assembly based on the conversion assembly.
In one embodiment of the invention, the controller moves the braking assembly to the disengaged position when the conversion assembly draws stock material from the stock supply roll and, in a further embodiment, to the engaged position when the conversion assembly stops drawing stock material from the stock supply roll.
According to another aspect of the invention, there is provided a method of converting sheet stock material into a three dimensional strip of cushioning. The method includes the steps of using a braking assembly, which is biased to apply a braking force to a stock supply roll, to prevent the stock roll from rotating, removing the braking force from the stock supply roll; and, using a conversion assembly to draw sheet stock material from the stock supply roll and convert the sheet stock material into a three dimensional strip of cushioning material.
In a preferred embodiment of the invention, the conversion assembly is stopped a braking force is automatically applied to the stock supply roll thereafter, thereby preventing overrun of the stock roll. Also, preferably the step of removing the braking force occurs substantially simultaneously as the step of using the conversion assembly. Also, a dancer device may also be used to help maintain a greater uniformity of tension in the stock material as it is being drawn by the conversion assembly. As is preferred, using the dancer device causes the braking force to be removed from the stock supply roll.
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 but non-limiting embodiments of the invention, such being indicative, however, of but one or a few of the various ways in which the principles of the invention may be employed.

Brief Description of the Drawings

Fig. 1 is a top plan view of the cushioning conversion machine in accordance with the present invention.
Fig. 2 is a side elevational view of the cushioning conversion machine of Fig. 1, the machine being shown in a horizontal manner, loaded with stock material, and with an outer housing side wall removed for clarity of illustration.
Figs. 3 and 4 are enlarged side views of a stock supply assembly of the Fig. 1 conversion machine, the stock supply assembly including a braking assembly shown in an engaged position in Fig. 3 and a disengaged position in Fig. 4.

Detailed Description

Referring now to the drawings in detail and initially to Figs. 1 and 2, a cushioning conversion machine is designated generally by reference number 10. The cushioning conversion machine 10 converts one or more plies of sheet stock material from a stock supply roll 11 into a dunnage product having, for example, lateral pillow-like portions separated by a thin central band. The dunnage product is used as an environmentally responsible protective packaging material typically used during shipping.
Referring more closely to Figs. 1 and 2, the conversion machine 10 includes a conversion assembly, indicated generally at 12, having an upstream end 14 and a downstream end 16. The sheet-like stock material enters the conversion assembly 12 through an opening 18 at the upstream end thereof for passage through the conversion assembly 12 where it is converted into a strip of cushioning material (dunnage product) that exits from the downstream end 16 of the conversion assembly 12.
The conversion assembly 12 includes a former or forming assembly 26 and a feeding/connecting assembly 28 powered (energized) by a feed motor 30, for example an electric motor, through a motion transfer assembly 32. Downstream of the feeding/connecting assembly, there is provided a severing assembly 34 (for example, a cutting assembly) powered by suitable means, such as the illustrated motor and motion transfer assembly 36. The forming assembly 26, feeding/connecting assembly 28 and severing assembly 34 are mounted to and/or in a housing 38 in a well-known manner. The operation of the conversion machine 10 may be controlled by a controller (not shown), also in a well-known manner. As will be apparent, other types of conversion assemblies may be employed for converting the sheet material into a three-dimensional strip of dunnage that is reduced to length by the severing assembly.
The illustrated exemplary forming assembly 26 includes a forming member 44, such as a forming frame, and a converging shaping chute 46. The forming assembly 26 causes an inward rolling or folding of the lateral edges of the sheetlike stock material to form a continuous strip of cushioning material having lateral pillow-like portions. The shaping chute 46 includes longitudinally extending, transversely converging side walls 50 which preferably are curved or arcuate in transverse cross-section. As the sheet-like stock material is passed through the shaping chute 46, the side edges thereof are turned or rolled inwardly towards one another so that the inwardly turned or rolled edges form resilient pillow-like crumpled portions of stock material disposed in lateral abutting relationship as they emerge from the exit end of the shaping chute. The forming member 44 coacts with the shaping chute 46 to ensure proper shaping and forming of the paper (or other suitable stock material), the forming member being operative to guide the central portion of the stock material along the bottom wall 54 of the shaping chute 46 for controlled inward rolling or folding of the side edge portions of the stock material. The forming member 44 projects rearwardly (upstream) of the entry end of the shaping chute for proper guiding of the stock material into the shaping chute. The forming member 44 also extends into the shaping chute with its forwardmost end disposed relatively close to the underlying bottom wall 54 of the shaping chute adjacent the exit end of the shaping chute, as shown.
The invention encompasses different types of feeding/connecting assemblies which perform a feeding and/or connecting function. However, a preferred feeding/connecting assembly 28 includes a pair of cooperating and opposed gears or gear- like members 60 and 62. The gears 60 and 62, and thus the feeding/connecting assembly 28, perform at least one and preferably two functions in the operation of the machine 10. One function is a "feeding" function, the gears pulling the stock material from the stock roll 11 and then through the forming assembly 26. The material is then discharged by the feeding/connecting assembly 28 to the severing assembly 34. The second function preferably performed by the feeding/connecting assembly 28 is a connecting function. Specifically, the feeding/connecting assembly 28 connects the continuous strip by the two opposing gears 60 and 62 coining the formed stock material along a central band to form a connected strip of cushioning material. Other mechanisms may be employed to "connect" the strip, i.e., to operate on the strip in such a manner that it will retain its cushioning properties as opposed to reverting to the original flat form of the stock material. Known connecting mechanisms include mechanisms that crease the stock material to enable the stock material to hold its three-dimensional shape.
The connected strip travels downstream from the feeding/connecting assembly 28 to the severing assembly 34 which severs, for example by cutting, the strip into a section of a desired length. The cut section then may travel through a post-cutting guide assembly such as in the manner described in commonly owned U.S. Patent No. 5,123,889, which includes a converging portion and rectangular tunnel portion. The coined or otherwise connected strip then emerges from the post-cutting guide assembly where an operator may remove the coined strip from the machine 10.
The conversion machine 10 also includes a stock supply assembly 66 which, as shown in the illustrated embodiment, includes a stock roll cradle assembly 68 for supporting the stock supply roll 11, a dancer device 70 for helping maintain a greater uniformity of tension in the stock material, and a braking assembly 72 for stopping the stock supply roll 11 at the completion of a conversion process.
The stock roll cradle assembly 68 includes a pair of laterally spaced apart mounting brackets 75 secured to the housing 38 of the conversion assembly 12. Rotatably mounted between the brackets 75 are a pair of parallel rotatable roll support members 80 and 81 (Fig. 2), constructed preferably of low friction material such as inox steel (stainless steel), that extend transverse to the path of the stock material and form a cradle in which the stock roll 11 lies. The roll support members 80 and 81 are in frictional engagement with an outer periphery of the stock roll 11 such that when stock material is drawn from the stock roll 11 by the conversion assembly 12 the stock roll 11 rotates counterclockwise (in Fig. 2) which, in turn, causes the roll support members 80 and 81 to rotate in the opposite direction, or clockwise (in Fig. 2). In this way, the roll support members 80 and 81 enable unwinding of the stock material while continuously providing support to the underside of the stock roll 11.
A pair of parallel guide roll support members 82 and 83 are also rotatably mounted between the brackets 75 and constructed preferably of low friction material such as inox steel (stainless steel). The guide rolls 82 and 83 assist in guiding the stock roll 11 as it is lowered onto the roll support members 80 and 81 from above the machine 10 and, during operation of the machine 10, assist in preventing the stock roll 11 from rocking outside of the cradle formed by the roll support members 80 and 81. Guide roll 82 also directs stock material drawn from the stock supply roll 11, in particular when the diameter of the stock roll 11 is relatively large as shown in Fig. 2, along a predetermined tangential path. The proximity (or moment arm) of the tangential path to the line of engagement of roll support member 80 reduces the likelihood of the stock supply roll 11 rocking or pivoting about the roll support member 80 when stock material is drawn from the stock roll 11.
The stock supply assembly 66 includes a pair of lateral stock roll guide members 90 and 92 (Fig. 1) disposed at opposite ends of the stock supply roll 11. The stock roll guide members 90 and 92 are constructed preferably of low friction material such as inox steel (stainless steel) and are preferably in the form of rollers that extend parallel to the radial direction of the stock roll 11. The ends of the rollers 90 and 92 are rotatably mounted in respective pairs of bearing mounts 94 and 96. The rollers 90 and 92 abut the edge of the stock roll 11 through respective openings 97 and 98 in the mounting brackets 75. As stock material is drawn from the stock supply roll 11, the abutting contact of the stock roll guide members 90 and 92 with the ends of the stock roll 11 assists in preventing lateral shifting of the stock supply roll 11 on the rotatable roll support members 80 and 81 and, therefore, facilitates stability during the conversion process and reduces the likelihood of tearing of the stock material during the initial unwinding of stock material from the stock supply roll 11.
The stock supply assembly 66 further includes a pair of laterally spaced apart mounting brackets 105 (Fig. 2) secured to the housing 38 of the conversion assembly 12. A constant entry roller 110 is rotatably mounted between the mounting brackets 105 and provides a non-varying point of entry for the sheet stock material from the stock roll 11. The brackets 105 also support therebetween a separating device which receives the sheet stock material from the constant entry roller 110 and separates multiple plies P₁ and P₂ of stock material from one another via vertically spaced apart and transversely extending separator members 112 and 114 (Fig. 2) prior to passing beneath the forming member 44 and into the shaping chute 46. For further details concerning the constant entry roller 110 and the separator members 112 and 114 reference may be had to U.S. Patent Application No. 09/229,459, which is owned by the assignee of the present invention.
Turning to Figs. 3 and 4, a dancer device 70 is rotatably mounted between the mounting brackets 105 for rotation about a dancer pivot axis 120. The dancer device 70 includes a dancer member 124, preferably in the form of an idler roller, which extends transverse to the path of the stock material and is rotatably mounted at its ends to a pair of dancer rocker arms 130. As is further described below, the dancer device 70 also includes a pair of pusher arms 132 which coact with a braking assembly 72 to cause the braking assembly 72 to impart or remove a braking force to/from the stock roll 11.
The dancer rocker arms 130 are rotationally biased about the dancer pivot axis 120 to a rest position in a manner to be further described below via respective connecting assemblies 134, including link members 135 and biasing members 136, with the biasing members 136 preferably in the form of tension springs. As is further described below, the biasing members 136 are designed and selected to maintain a cooperating relationship between the dancer device 70 and the braking assembly 72.
In the rest position, the idler roller 124 forms a generally sinusoidal loop in the stock material thereby to take up slack therein as shown, for example, in Fig. 3. Stops 138 are mounted to the brackets 105 in the path of the dancer rocker arms 130 to absorb backlash or other sudden impact type of movements the dancer rocker arms 130 may experience, for example, as may occur when the conversion assembly 12 is suddenly stopped and/or the tension in stock material suddenly drops.
As stock material is drawn from the stock roll 11 the tension in the stock material increases, imparting a load to the dancer member 124 which causes the dancer rocker arms 130 to rotate about the dancer pivot axis 120 (clockwise in Figs. 3 and 4). As the load reaches a predetermined level, the bias of the biasing members 136 is overcome and the dancer member 124, by virtue of its mounting on dancer rocker arms 130, starts pivoting about the dancer pivot axis 120 (clockwise in Fig. 4). In this way, the dancer device 70 "absorbs" excessive tension in the stock material created by loads in excess of the predetermined level, thereby assisting in maintaining the tension in the stock material substantially uniform.
It will be appreciated that the rotational bias imparted by the biasing members 136 to the dancer rocker arms 130 permits a range of tensions in the stock material. For example, the tension in the stock material is greater for that which is shown in Fig. 4 than for that which is shown in Fig. 3. Also, as described in greater detail below, the biasing members 136 preferably additionally function to bias the braking assembly 72 to apply a braking force to the stock roll 11 (e.g., when a conversion process is completed or the conversion assembly 12 is otherwise stopped), thereby bringing and/or maintaining the stock roll 11 to/in a rest position, when there is no tension in the stock material.
The braking assembly 72 includes a pair of braking rocker arms 140 rotatably mounted to the respective mounting brackets 75 via a brake pivot axis 142, and a brake member 144 which extends transverse to the path of the stock material and is mounted at its ends to the respective braking rocker arms 140 on ends 146 thereof proximate to pivot axis 142. Although the as-shown brake member 144 is in the form of a cylindrical roll, it will be appreciated that the brake member 144 may take on other suitable geometrical configurations. The brake member 142 is constructed preferably of a high friction material or, alternative, may be covered, for example, by rubber or other suitable friction enhancing material.
The brake member 144 is pivotably movable about the brake pivot axis 142 between a brake engaged position (Fig. 3) and a brake disengaged position (Fig. 4). In the brake engaged position, the brake member 144 frictionally engages the rotatable roll support member 81, preventing its rotation, and thereby preventing rotation of the stock supply roll 11 in frictional engagement therewith. In the brake disengaged position, the brake member 144 is retracted from engagement with the rotatable roll support member 81, thereby permitting rotation of the stock supply roll 11. Stops 148 are mounted to the brackets 75 in the path of ends 151 of braking rocker arms 140 distal from its pivot axis 142 to limit the rotation of the braking rocker arms 140 about the pivot axis 142, their most downward position being shown in Fig. 4.
In the illustrated exemplary embodiment, the braking rocker arms 140 are rotationally biased by the same biasing members 136 which bias the respective dancer rocker arms 130. As shown in Figs. 3 and 4, each biasing member 136 has a first end 150 connected to the braking rocker arm 140 at an end 146 at which the brake member 144 is mounted, and a second end 152 connected to an adjacent end of each link member 135, with an opposite end 154 of each link member 135 being rotatably connected to dancer rocker arm 130 at an end 156 opposite the end at which the dancer member 124 is mounted. The dancer device 70 includes respective pusher arms 132 extending at substantially right angles from the respective dancer rocker arms 130 near their ends 156. The pusher arms 132 momentarily contact underside portions 164 of the respective braking rocker arms 140. The pusher arms 132 maintain a predetermined distance between the ends 156 of the dancer rocker arms 130 and the ends 146 of the braking rocker arms 140 over a predetermined range of movements in the dancer device 70, the range in the illustrated embodiment being from the position shown in Fig. 3 to the position shown in Fig. 4.
As can be appreciated by the foregoing arrangement, the biasing members 136, together with link members 135, maintain a relative bias between the dancer device 70 (more particularly, the dancer rocker arms 130 and the pusher arms 132) and the respective braking rocker arms 140 at the respective connection points 150 and 154 which varies in function depending on the position of the pusher arms 132 relative to the braking rocker arms 140. Thus, in Fig. 3, wherein there is no tension in the stock material, the biasing members 136 urge the ends 156 of the dancer rocker arms 130 and the ends 152 of the braking rocker arms 140 towards one another. In so doing, the pusher arms 132 exert an upward load on the respective underside portions 164 of the braking rocker arms 140 which, in turn, urges the braking rocker arms 140 about the brake pivot axis 142 (clockwise in Fig. 3), urging the brake member 144 into frictional engagement with the roll support member 81, and thereby bringing and/or maintaining the stock roll 11 to/in a rest position.
Referring to Fig. 4, when a predetermined amount of tension is imparted to the stock material, the dancer rocker arms 130 rotate about the dancer pivot axis 120, causing the respective ends 156 thereof to pull the ends 154 of the connecting assemblies 134 downward which, in turn, causes the pusher arms 132 to move downward. Also, the biasing members 136 of the connecting assemblies 134 bias, or pull, the ends 146 of the braking rocker arms 140 toward the ends 156 of the dancer rocker arms 130 as the pusher arms 132 maintain their contact with the underside portions 164 of the respective braking rocker arms 140. The braking rocker arms 140 rotate (counterclockwise in Fig. 4) until the ends 151 of the braking rocker arms 140 contact the stops 148. As a result, the brake member 144 mounted between the braking rocker arms 140 is retracted from the roll support member 81, thereby removing the braking force therefrom and enabling the roll support member 81 to freely rotate and, consequently, the stock supply roll 11 to freely rotate.
As was mentioned above, the spring constants of the biasing members 136 are selected to maintain a cooperative relationship between the dancer device 70 and the braking assembly 72. For example, with reference to Fig. 3, wherein there is no load being exerted on the dancer member 124, the spring constants are selected so that the connecting assemblies 134 urge the ends 156 of the dancer rocker arms 130 and the ends 146 of the braking rocker arms 140 towards one another, which urges the brake member 144 into engagement with the rotatable roll support member 81 as above described. In this regard, the greater the spring constant, the greater is the load imparted to the brake member 144. With reference to Fig. 4, the spring constants are also selected so that the predetermined tension required to rotate the dancer rocker arms 130 and thereby retract the brake member 144, overcomes the bias in the biasing members 136 as above described.
Other factors, such as the size, dimensions and weight of the respective dancer rocker arms 130, pusher arms 132 and braking rocker members 140, and their positional relationships, may also be modified to effect changes in the brake load and/or the predetermined tension required to overcome the bias in the biasing members 136. To this end, the illustrated dancer rocker arms 130 and pusher arms 132, as well as the dancer member 124 mounted between the dancer rocker arms 130, may be designed to provide a rotational bias (either clockwise or counterclockwise in Fig. 3, and either by gravity or other means) about the dancer pivot axis 120 when the conversion machine 10 is in a rest position. Similarly, the illustrated braking rocker arms 140, as well as the brake member 144 mounted between the braking rocker arms 140, may be designed to provide a rotational bias (either clockwise or counterclockwise in Fig. 3, and either by gravity or other means) about the brake pivot axis 142. For example, in the illustrated embodiment, the dancer device 70 may be designed to be counterclockwise rotationally biased and the braking assembly 72 may be designed to be clockwise rotationally biased so that, in the event the biasing members 136 were to fail, the brake member 144 would be urged into engagement with the roll support member 81 by means of the combined biasing forces acting on the brake member 144.
It will be appreciated then that the cooperative relationship between the dancer device 70 and the braking assembly 72 of the present invention provides automatic activation of the dancer device 70 (and simultaneous deactivation of the braking assembly 72) when a predetermined level of tension is imparted to the stock material, and automatic braking of the stock supply roll 11 (and simultaneous deactivation of the dancer device 70) when the conversion process is completed or the conversion assembly 12 is otherwise not drawing stock material from the stock supply roll 11.
It will also be appreciated that the previously described automatic activation and deactivation of the dancer device 70 and braking assembly 72 may be achieved in alternative ways, and such alternatives are contemplated as falling within the scope of the presently claimed invention. For example, in an alternative embodiment (not shown), the dancer device 70 functions as a braking assembly (with the illustrated braking assembly 72 being omitted) whereby the pusher arms 132 automatically engage and disengage with the rotating roll support member 81 based on the response (of the dancer rocker arms 130 and, more particularly, the pivoting dancer member 124 thereof) to tension in the stock material being drawn by the conversion assembly 12. In such an embodiment, the pusher arms 132 have attached to their distal ends a brake member (not shown) which engages the roll support member 81 when the conversion process is stopped and retracts from the roll support member 81 when tension is imparted to the stock material, at which time the dancer device 70 would function in a manner similar to that described above, helping to maintain a greater uniformity of tension in the stock material being fed through the conversion assembly 12. A suitable biasing member, such as the aforementioned biasing member 136, is used to bias the dancer rocker arms 130 and, more particularly, the pusher arms 132, to the brake engaged position.
In another embodiment (not shown), a controller is used to activate and/or deactivate a dancer device and braking assembly (with the illustrated connecting assemblies 134 between the dancer device 70 and braking assembly 72 being omitted). The conversion machine is equipped with a limit switch which is triggered by, for example, rotation in the dancer rocker arms between a rest position and one or more activated positions. Thus, for example, when the dancer rocker arms are in a rest position the switch transmits a signal to the controller to activate the braking assembly, thereby preventing rotation of the stock roll. When the stock material imparts a load on the pivoting dancer member mounted between the dancer rocker arms, the switch transmits a signal to the controller to deactivate the braking assembly, thereby permitting the stock roll to freely rotate. Alternatively, the braking assembly may be deactivated by the controller upon initiation of a conversion process, for example upon start-up of the conversion assembly, and activated by the controller upon completion of a conversion process, as when the conversion assembly is shut off or placed in a stand-by mode. In such an embodiment, the braking assembly may include biasing members which bias the brake member into a brake position when the dancer rocker arms are in a rest position and an actuator, such as a solenoid, which retracts the brake member when instructed by the controller. Alternatively, the braking assembly may include a reciprocating actuator which applies or retracts the brake member in accordance with instructions from the controller.
It is noted that, because the invention was conceived and developed in the context of a stock supply assembly embodying a cradle configuration, it has been described herein chiefly in such context. However, the underlying principles of the invention could be adapted to other configurations of stock supply assemblies, for example, in applications wherein the stock supply roll is axially mounted. In this regard, in the illustrated embodiment the stock supply roll may be mounted to a spindle journalled at its opposite ends (not shown) to permit rotation of the stock roll about an axis passing through the spindle. (Thus, the illustrated rotatable roll support members 80 and 81 and guide roll support members 82 and 83 are omitted.) In such an embodiment, drums having a diameter slightly larger than the diameter of the stock roll are mounted to the ends of the spindle. The braking assembly is positioned to impart and similarly to retract a braking force to (from) the drum by any of the above mentioned methods.
Although the invention has been shown and described with respect to certain preferred embodiments, equivalent alterations and modifications will occur to others skilled in the art upon reading and understanding this specification and the annexed drawings. In particular regard to the various functions performed by the above described integers (components, assemblies, devices, compositions, etc.), the terms (including a reference to a "means") used to describe such integers are intended to correspond, unless otherwise indicated, to any integer which performs the specified function of the described integer (i.e., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein illustrated exemplary embodiment or embodiments of the invention. In addition, while a particular feature of the invention may have been described above with respect to only one of several illustrated embodiments, such feature may be combined with one or more other features of the other embodiments, as may be desired and advantageous for any given or particular application.

Claims

A cushioning conversion machine comprising:

a conversion assembly for drawing sheet stock material from a stock supply roll whereby the stock supply roll is rotated, and for converting the stock material into a three dimensional strip of cushioning material; and,

a stock supply assembly for supporting the stock supply roll, the stock supply assembly including a braking assembly movable between a brake engaged position whereby a braking force is imparted to the stock supply roll to prevent the stock supply roll from rotating, and a brake disengaged position whereby the braking force is removed from the stock supply roll thereby permitting the stock supply roll to rotate;

wherein the braking assembly is biased to the brake engaged position by a biasing member and is urged to the brake disengaged position by a force overcoming the bias.
A cushioning conversion machine as set forth in claim 1, wherein the force overcoming the bias of the biasing member is related to tension generated in the stock material between the stock supply roll and the conversion assembly.
A cushioning conversion machine as set forth in claim 1, wherein the biasing member comprises a tension spring.
A cushioning conversion machine as set forth in claim 1, wherein the stock supply assembly further includes a dancer device and the braking assembly includes a brake rocker arm, the dancer device being operative to move the brake rocker arm between the brake engaged position and the brake disengaged position based on changes in tension in the stock material between the stock supply roll and the conversion assembly.
A cushioning conversion machine as set forth in claim 4, wherein the biasing member is positioned to maintain the brake rocker arm and the dancer device in coacting relationship with each other as stock material is drawn by the conversion assembly.
A cushioning conversion machine as set forth in claim 4, wherein the biasing member has opposite end portions, one end being connected to the brake rocker arm and the other end being connected to the dancer device.
A cushioning conversion machine as set forth in claim 4, wherein the dancer device is rotatable about a dancer pivot axis and the biasing member rotationally biases the dancer device about the dancer pivot axis.
A cushioning conversion machine as set forth in claim 7, wherein the dancer device includes a dancer member which is radially offset from the dancer pivot axis and is positioned so that sheet stock material drawn from the stock supply roll is trained about an arcuate portion of the dancer member, and wherein, when the sheet stock material is drawn from the stock supply roll, the load on the dancer member is substantially countered by the rotational bias in the dancer device, thereby helping to maintain a greater uniformity of tension in the sheet stock material.
A cushioning conversion machine as set forth in claim 7, wherein the stock supply assembly includes a stop for limiting rotational movement of the dancer device.
A cushioning conversion machine as set forth in claim 4, wherein the brake rocker arm is rotatable about a brake pivot axis and the biasing member rotationally biases the brake rocker arm about the brake pivot axis.
A cushioning conversion machine as set forth in claim 10, wherein the stock supply assembly includes a stop for limiting rotational movement of the brake rocker arm.
A cushioning conversion machine as set forth in claim 1, wherein the stock supply assembly includes one or more rotatable roll support members that extend transversely to the path of the stock material and engage an outer periphery of the stock supply roll and wherein when the braking assembly is in the brake engaged position the braking force is applied to at least one of the rotatable roll support members to prevent the stock supply roll from rotating.
A cushioning conversion machine as set forth in claim 12, wherein the stock supply assembly includes a pair of stock roll guide members disposed at opposite ends of the stock supply roll for preventing lateral shifting of the stock supply roll on the rotatable roll support members.
A cushioning conversion machine as set forth in claim 13, wherein the stock roll guide members comprise stock roll guide rollers.
A cushioning conversion machine as set forth in claim 1, wherein the stock supply roll is mounted to a spindle journalled at its opposite ends, the spindle having a drum fixedly mounted to at least one of its ends, and wherein when the braking assembly is in the brake engaged position the braking force is applied to the drum to prevent the stock supply roll from rotating.
A cushioning conversion machine comprising:

a conversion assembly for drawing sheet stock material from a stock supply roll whereby the stock supply roll is rotated, and for converting the stock material into a three dimensional strip of cushioning product; and,

a stock supply assembly for supporting the stock supply roll, the stock supply assembly including a dancer device for helping maintain a greater uniformity of tension in the stock material as stock material is drawn from the stock supply roll, wherein the dancer device includes a brake member which automatically imparts a braking force to the stock supply roll when stock material is not being drawn from the stock supply roll to prevent the stock supply roll from rotating.
A cushioning conversion machine comprising:

a conversion assembly for drawing sheet stock material from a stock supply roll whereby the stock supply roll is rotated, and for converting the stock material into a three dimensional strip of cushioning; and,

a stock supply assembly for supporting the stock supply roll, the stock supply assembly including a braking assembly movable between a brake engaged position wherein a braking force is imparted to the stock supply roll to prevent the stock supply roll from rotating, and a brake disengaged position wherein the braking force is removed from the stock supply roll thereby permitting the stock supply roll to rotate;

wherein the braking assembly is operative to move between the brake engaged position and the brake disengaged position based on the tension in the stock material being drawn by the conversion assembly.
A cushioning conversion machine comprising:

a conversion assembly for drawing sheet stock material from a stock supply roll whereby the stock supply roll is rotated, and for converting the stock material into a three dimensional strip of cushioning material;

a stock supply assembly for supporting the stock supply roll, the stock supply assembly including a braking assembly movable between a brake engaged position whereby a braking force is imparted to the stock supply roll to prevent the stock supply roll from rotating, and a brake disengaged position whereby the braking force is removed from the stock supply roll thereby permitting the stock supply roll to rotate; and,

a controller for controlling the braking assembly based on the conversion assembly.
A method of converting sheet stock material into a three dimensional strip of cushioning, comprising the steps of:

using a braking assembly, which is biased to apply a braking force to a stock supply roll, to prevent the stock roll from rotating;

removing the braking force from the stock supply roll; and,

using a conversion assembly to draw sheet stock material from the stock supply roll and convert the sheet stock material into a three dimensional strip of cushioning material.