WO2025184121A1

WO2025184121A1 - Assembly and method for securing a roll of dunnage stock material on a spindle

Info

Publication number: WO2025184121A1
Application number: PCT/US2025/017262
Authority: WO
Inventors: Koen RAS
Original assignee: Ranpak Corp
Current assignee: Ranpak Corp
Priority date: 2024-03-01
Filing date: 2025-02-25
Publication date: 2025-09-04
Anticipated expiration: 2026-09-01

Abstract

A roll lock assembly (100) for securing on a spindle (93) a roll of packaging material (91) having a hollow core, the roll lock assembly comprising: a cylinder including an opening extending partially through a side of the cylinder, and a passage along a longitudinal axis of the cylinder that is configured to receive the spindle; a lever (112), disposed in the opening of the cylinder, movable between a raised position that extends proud of the opening in the cylinder, and a lowered position that is substantially flush with the cylinder; and a biasing mechanism, to bias the lever to the raised position.

Description

ASSEMBLY AND METHOD FOR SECURING A ROLL OF DUNNAGE STOCK MATERIAL ON A SPINDLE

Field of the Invention

This disclosure relates generally to the field of dunnage conversion, and more particularly to an apparatus for retaining a roll of sheet stock material in an operating position relative to a dunnage conversion machine.

Background

In the process of transporting an item from one location to another, a dunnage product typically is placed in a container to fill any voids around the item and/or to cushion the item during the transportation process. Dunnage conversion machines, also referred to as converters, generally convert a sheet stock material into a relatively less dense dunnage product, to protect articles in a shipping container during shipment. Some converters produce a dunnage product primarily intended to fill voids in a packaging container to prevent the contents from shifting during shipment, while other converters produce a dunnage product that provides more cushioning from impact or vibration.

Many suitable dunnage products can be produced from a sheet stock material, such as paper or plastic. The sheet stock material usually is supplied in the form of a roll or a fan-folded stack from which the sheet stock material is paid off or drawn off for conversion by the machine into the dunnage product. Rolls of sheet stock material typically have a hollow core around which the sheet stock material is wound and are supported on a spindle that allows the roll to rotate as the conversion machine draws the sheet stock material from the roll.

Summary

One problem in some dunnage conversion machines that draw sheet material from rolls is that the spindle over which a hollow core of the roll of sheet stock material is mounted for rotation can become bent or otherwise damaged during use. This is a particular problem in the case of cantilevered spindles that are supported at only one end. As a result, the roll can slide along the length of the spindle and move out of a proper position on the spindle, impeding the withdrawal of the sheet stock material from the spindle and into a dunnage conversion machine. When the conversion machine cannot properly retrieve the stock material, the conversion machine can stop functioning and/or create deficient dunnage. Previously, this would require the conversion process to stop and a new spindle, or a spindle repair, would be required to resume operation.

The present disclosure provides a solution to these problems in the form of a locking assembly for retaining a roll of sheet stock material on a spindle to minimize, prevent, or adapt to a bent or otherwise damaged spindle.

The assembly includes a cylinder having a slot along a side of the cylinder that is configured to receive a lever and a biasing mechanism. The cylinder also includes a passage along the longitudinal axis of the cylinder, parallel to a height dimension of the cylinder, to an opening at one end of the cylinder. The passage is configured to receive the spindle. Transverse holes through the curved section of the cylinder facilitate securing the lever to the cylinder.

The lever is rotatably secured to the cylinder and is movable between a raised or deployed position, extending from the slot to stand proud of the surface of the cylinder, and a lowered position with the lever substantially contained within the slot or approximately flush with the surface of the cylinder. In the raised position, the lever is configured to engage the roll of sheet stock material to ensure that the roll of sheet stock material remains in its intended position on the spindle. In the lowered position, the lever is substantially contained within the slot to allow a hollow core of a stock roll to pass over the lever and the assembly onto the spindle without removing the assembly from the spindle. The biasing mechanism biases the lever to the raised position.

An exemplary roll lock assembly for securing on a spindle a roll of packaging material having a hollow core, comprises a cylinder including an opening extending partially through a side of the cylinder, and a passage along a longitudinal axis of the cylinder that is configured to receive the spindle; a lever, disposed in the opening of the cylinder, movable between a raised position that extends proud of the opening in the cylinder, and a lowered position that is substantially flush with the cylinder; and a biasing mechanism, to bias the lever to the raised position.

According to one or more embodiments, the roll lock assembly further includes a housing compartment configured to receive the biasing mechanism.

In one or more embodiments, the housing component is configured to receive the biasing mechanism is located inside of the opening of the cylinder.

In one or more embodiments, the cylinder is configured to have a compartment designed to receive the lever.

In one or more embodiments, the opening extending through the side of the cylinder is trough shaped.

In one or more embodiments, the cylinder has a diameter that is less than or equal to a diameter of the spindle to which the roll lock assembly is configured to attach.

In one or more embodiments, the lever has a top surface, and the cylinder has a bottom point and while the lever is in the lowered position, a distance between the top surface of the lever and the bottom point of the cylinder is less than a diameter of the hollow core of the roll of packaging material.

In one or more embodiments, the lever’s top surface is inside the opening of the cylinder while the lever is in the lowered position.

In one or more embodiments, the top surface of the lever is flat. In one or more embodiments, the lever further comprises a first opening that cooperates with a first pin extending into the first opening, where the first pin is attached to the cylinder and defines an axis about which the lever can rotate.

In one or more embodiments, the lever further comprises a second opening that cooperates with a second pin extending into the second opening, connected to the cylinder, to define an angular range of motion of the lever.

In one or more embodiments, in combination with the roll of packaging material, when in the raised position, the lever engages a surface of the roll of packaging material.

In one or more embodiments, in combination with the roll of packaging material, the lever engages an outer surface of the hollow core.

In one or more embodiments, the lever is configured to have a blunt tip at a distal end.

In one or more embodiments, the biasing mechanism is elastic.

In one or more embodiments, the biasing mechanism is a spring.

In one or more embodiments, the passage along the length of the cylinder has an internal surface, configured to secure the assembly to the spindle.

An exemplary method of securing on a spindle a roll of packaging material having a hollow core includes providing a cylinder having an opening extending partially through a side of the cylinder, and a passage along a longitudinal axis of the cylinder that is configured to receive the spindle; providing a lever, disposed in the opening of the cylinder, movable between a raised position that extends proud of the opening in the cylinder, and a lowered position that is substantially flush with the cylinder; and providing a biasing mechanism, to bias the lever to the raised position.

These and other features of the apparatus are fully described and particularly pointed out in the claims. The following description and annexed drawings set forth in detail one illustrative embodiment of the apparatus, this embodiment being indicative of but one of the various ways in which the principles of the apparatus may be employed.

Brief Description of the Drawings

FIG 1 is a schematic illustration of a dunnage conversion operation,

FIG 2 is a perspective view of an exemplary roll lock assembly mounted on a spindle to retain a roll of sheet stock material for conversion into a dunnage product by a dunnage conversion machine,

FIG 3 is a perspective view of the roll lock assembly of FIG 2 removed from the spindle,

FIG 4 is an alternate perspective view of the roll lock assembly of FIG 3 with the lever removed,

FIG 5 is a cross-sectional view of the roll lock assembly of FIG 2,

FIG 6 is an alternate view of the roll lock assembly of FIG 3 with the lever removed,

FIG 7 is side view of an exemplary lever of the roll lock assembly of FIG 2,

FIG 8 is a perspective view of the lever of FIG 7, and

FIG 9 is a perspective view of an exemplary spindle configured to accept the roll lock assembly of FIG 2. Detailed Description

Dunnage conversion machines typically operate to produce dunnage products on demand, as needed, which typically results in frequent start-stop operation. A typical dunnage conversion process is schematically depicted in FIG 1. A conversion machine 90 draws sheet stock material from a feedstock, specifically a supply of sheet stock (interchangeably referred to as sheet stock material) 91 , whereby the sheet stock is converted into dunnage material 93 (interchangeably referred to as a discrete dunnage product or simply dunnage) for use in packaging.

An exemplary supply of sheet stock 91 includes a sheet material wound into a roll and supported by a spindle 93 for rotation. For dunnage conversion machines that draw a sheet stock material from a roll for conversion into a relatively lower density dunnage product, every start requires the conversion machine to overcome the inertia of the stationary roll to draw sheet material therefrom. And every stop allows the inertia of the roll to continue to rotate and dispense a loose segment of sheet material that is not drawn into the conversion machine. Restarting the conversion machine then causes the conversion machine to impart a sudden increase in tension on the stock material as the slack is taken up. This sudden increase in tension in the stock material is imparted to the roll, as well as to the spindle 93 that supports the roll for rotation.

The weight of the roll and the repeated tension transmitted through the stock material can damage the spindle 93 and allow the roll to move laterally along the spindle, impeding the withdrawal of stock material from the roll and into the conversion machine. When the conversion machine cannot properly retrieve the stock material, the conversion machine can stop functioning or create deficient dunnage. Previously, this would require the conversion process to stop and a new spindle, or a spindle repair, would be required to resume operation.

The present disclosure provides a solution to these problems in the form of a roll lock assembly for retaining the roll of sheet stock material in its initial intended position on the spindle to minimize, prevent, or adapt to a bent or otherwise damaged spindle.

A typical dunnage conversion machine 90 includes a forming assembly 94 that shapes the sheet stock material and a feeding assembly 95 that draws the sheet material in an upstream-to-downstream direction from a supply and through the forming assembly. The upstream-to-downstream direction also can be referred to as a downstream direction, and an upstream direction is opposite the downstream direction. The conversion machine optionally may include a severing assembly 96 for severing discrete lengths of dunnage at desired lengths as it is produced. The conversion machine also can include a controller 97 with a microprocessor 98, a memory 99, and software that controls the conversion machine 90, typically at least the feeding assembly 107 and the severing assembly 108, to produce the desired lengths of dunnage 92.

The supply of sheet stock material 91 is provided in the form of a roll, and an exemplary sheet material is paper, such as kraft paper. The roll of sheet material may have a single ply, or multiple plies, and may be perforated at regular intervals to facilitate producing predetermined lengths of dunnage product without cutting the stock material. Rolls of sheet material are typically wound around a hollow core. The hollow core may be reusable after depletion of the stock material, or the core may be removed after winding to form a “coreless” roll of stock material. The core may include a stiff tubular structure, such as a cardboard, paperboard, or plastic tube. Alternatively, a coreless roll may have a hollow cylindrical volume at its center. Any of these types of roll may be referred to as a “hollow core” roll of sheet material.

The roll of sheet stock material 91 is mounted on a spindle 93 that allows the roll to rotate as the dunnage conversion machine 90 draws the sheet stock material from the roll. A roll lock assembly 100 is used to retain the roll on the spindle 93 and allow hollow core rolls and depleted cores to be removed from the spindle 93 without removing the roll lock assembly 100.

Turning to FIG. 2, the spindle 93 is mounted to the machine 90 or a separate support in a cantilevered fashion, with only at a proximal end 101 supported and a distal end 102 extending away from the support structure. An exemplary roll lock assembly 100 is mounted to the distal end 102 of the spindle 93 and includes a cylinder 111 having an opening or slot 114 along a side of the cylinder that is configured to receive a lever 112. The lever 112 is designed to engage a surface of the roll of sheet stock material 91 . More specifically, in the illustrated embodiment, the lever 112 engages an outer side surface of rolled layers of sheet stock material of the roll of sheet stock 91 . Alternatively, the lever may engage a core of the roll of sheet stock material.

Turning now to FIGS. 3 - 6, which illustrate an exemplary roll lock assembly 100 in isolation. The cylinder 111 includes a passage 130 along the longitudinal axis of the cylinder 111 , parallel to a height dimension of the cylinder, to an opening at one end of the cylinder 111. The passage 130 is configured to receive the spindle so that the roll lock assembly can be mounted on and secured to the spindle 93. FIG 3 shows transverse through-holes 132, which are attachment points in the side of the curved portion of the cylinder 111 that are used to connect the cylinder 111 to the lever 112 via pins 218, 220 or other fasteners. The pins secure the lever 112 to the cylinder 111 and to help define a range of motion for the lever 112. The illustrated embodiment uses two pins and four attachment points, which are depicted as holes 132, two holes on one side of the cylinder with matching holes on the opposite side of the cylinder (See also, FIG 6). Two separate pins are inserted into two separate holes 132 on one side of the cylinder 111. The two pins 218, 220 pass through the first set of attachment holes 132, then pass through the base of the lever 112, to secure the lever 112 to the cylinder 111. The pins extend through two opposing attachment holes 132 on the opposite side of the curved portion of the cylinder 111 . The pins can be any means to secure the lever to the cylinder, such as threaded screws or bolts, dowel rods with no threading, clips, wire, or any other known fastener or attachment means. The number of attachment points or pins is not critical, but at least one point of attachment is necessary to retain the lever.

The lever 112 is rotatably secured to the cylinder 111 and is movable between a raised or deployed position, extending from the slot 114 to stand proud of the surface of the cylinder 111 (as shown in FIG 3), and a lowered or retracted position with the lever 112 substantially flush or substantially contained within the slot 114 or at least approximately flush with the surface of the cylinder 111 (as shown in FIG 5). By substantially or approximately flush, it is meant that the lever is retracted or lowered to a sufficient extent that the core of the roll of sheet stock is not blocked or otherwise impeded by the lever during installation of a new roll, or extraction of the core of a spent roll. A biasing mechanism 116 biases the lever 112 to the raised position. In the raised position, the lever 112 is configured to engage the roll of sheet stock material 91 to ensure that the roll of sheet stock material 91 remains in place on the spindle 93 and does not slide or travel down the length of the spindle during operation. In the lowered position, the lever 112 is substantially contained within the slot 114 to allow a hollow core of a stock roll 91 to pass over the lever 112 and the assembly 100 onto the spindle 93 without removing the roll lock assembly 100 from the spindle 93.

FIG 5 shows a cross-sectional view of an exemplary roll lock assembly 100. The lever 112 is attached cylinder 111 by the pins 218, 220, and is biased to the raised position by the biasing mechanism 116. The biasing mechanism 116 can be any means to bias the lever 112 to a desired position, such as a type of spring or an elastic element. The biasing mechanism 116 is interposed between the lever 112 and the cylinder 111. In the illustrated embodiment, the opening or slot 114 in the cylinder 111 includes a housing compartment 117 configured to receive the biasing mechanism 116, which is formed by a coil spring in the illustrated embodiment.

The cylinder 111 has a diameter that is equal to the diameter of the spindle 93, to which the cylinder 111 is configured to attach. The diameter of the cylinder can also be less than the diameter of the spindle to facilitate installing a new roll of sheet material. The cylinder 111 attaches to the spindle 93 via the passage 130 along the longitudinal axis of the cylinder 111 that is configured to receive the spindle 93. The passage 130 extends from a hole on an end surface of the cylinder 111 , to provide an access point for the passage to receive the spindle 93. The passage 130 has an internal surface 131 configured to secure the assembly to the spindle. To secure the spindle, the internal surface 131 of the passage 130 may include a friction grip, a threaded design that cooperates with a corresponding threaded design on the distal end of the spindle, or any other known method of attachment. A transverse hole intersecting the passage may be provided for a set screw or other fastener to secure the roll lock assembly 100 to the spindle 93.

Turning now to FIGS. 7 and 8, which show an exemplary lever 112 of the roll lock assembly 100. The lever 112 has a first opening 118 at a proximal end that cooperates with a first pin 218 configured to pass through the opening 118, where the first pin 218 is mounted to the cylinder via one or more cylinder holes 132. The first opening 118 and the first pin 218 cooperate to define an axis about which the lever 112 can rotate.

The illustrated lever 112 also contains a second opening 120 in the shape of an elongated slot that cooperates with a second pin 220 that passes though one or more cylinder holes 132 and extends through the second opening 120. The second opening 120 further secures the lever 112 to the cylinder 111 and defines an angular range of motion for the lever 112 as it moves between the raised position and the lowered position.

An upper portion of the lever 112 has an angled surface 126 and a flat topmost surface 125. The flat top surface 125 of the lever is configured to be partially or completely retracted inside the opening 114 of the cylinder 111 while the lever 112 is in the lowered position. When in the lowered position, the distance between the uppermost surface of the lever 112 and the cylinder’s bottom point is less than the diameter of the hollow core of the roll of packaging material 91 . This allows the surface of the retracted lever to be approximately flush with or recessed below the surface of the cylinder, as shown in FIG. 5, for example. This also allows the hollow core of the roll of packaging material 91 to pass over the roll lock assembly 100 and onto or off of the spindle 93 without interference from the lever 112. The angled nature of the angled surface 126 also facilitates installing a fresh roll over the roll lock assembly 100. As the core of the roll is placed over the roll lock assembly 100, the roll will contact the angled surface 126 and automatically push the lever 112 downward, toward the lowered position, as the roll advances onto the spindle 93.

The illustrated lever 112 has a blunt or rounded tip 122 at the distal end 123. The blunt tip 122 is configured to engage the roll of dunnage sheet stock 91 without cutting, scoring, or otherwise damaging the sheet stock.

The illustrated lever has a notch 124 below the distal end 123 of the lever 112 that allows the lever 112 to avoid the internal geometry of the slot 114 in the cylinder 111 when the lever 112 is depressed into the slot 114 in the lowered position. Alternative embodiments may have a different shape as long as the slot has a geometry that permits the lever to be received in the slot in the lowered position.

FIG. 9 shows an exemplary end of spindle 93 having a mounting means 150 that engages with passage 130 of the roll lock assembly 100 to attach the roll lock assembly to the spindle. The mounting means 150 can be threaded member, a friction-fit peg, or other attachment means known in the art. The mounting means can be formed as part of the spindle 93, or it can be a separate member that is attached to the spindle 93. Accordingly, the spindle 93 can have a passage 151 that can accept the mounting means 150. The spindle passage 151 and the mounting means 150 can be joined by a threaded connection, a friction-fit connection, welded together, glued together, or other attachment means known in the art. For example, the mounting means 150 can be a threaded rod that screws into spindle passage 151 and screws into roll lock assembly passage 130 to affix the roll lock assembly 100 to the spindle 93.

The combination of all these components creates beneficial results. The first result is that the roll lock assembly provides a physical barrier to lateral movement of the roll of sheet stock, such that the roll is retained in its installed position and does not slide or move out of position during operation. In addition, an operator does not have to remove the roll lock assembly either to install a new roll of sheet stock material onto the spindle, or to remove a depleted hollow core of the roll of sheet stock material from the spindle. Due to the ability of the roll of sheet stock material to engage the lever and drive it downward against the biasing force applied to the lever by the biasing mechanism, simply pushing a roll onto the roll lock assembly and over the spindle automatically pushes the lever toward the lowered position, approximately flush with the surface of the cylinder of the roll lock assembly with minimal effort from the operator. Once the roll passes the distal end of the lever, the biasing mechanism automatically moves the lever to the raised position to engage the end of the roll. In other words, during installation of a fresh roll of sheet stock, the edge of the roll engages the angled surface of the lever, causing the lever to move down to the lowered position, compressing the spring. After the roll of sheet stock material passes the lever on the assembly, the spring biases the lever towards the raised position proud of the surface of the cylinder to prevent the roll of sheet stock material from backsliding out of position and/or off the spindle. To remove the roll of sheet stock material from the spindle, an operator would manually depress the lever until the lever is in the lowered position, allowing the operator to slide the depleted hollow core of the roll of sheet stock material over the distal end of the lever, which is approximately or substantially flush with the cylinder, or recessed below the surface of the cylinder. Once the hollow core is over the distal end of the lever, since the uppermost surface of the lever is approximately flush with the surface of the cylinder, the operator can easily slide the roll the rest of the way off of the spindle and assembly without interference from the lever.

The blunt tip on the end of the lever ensures there is no damage to the roll of sheet stock material or to the core of the roll of sheet stock material. The blunt tip is shaped so as to not cut into the sheet stock material. In addition, the lever easily slides across the hollow core of the roll of sheet stock material as the roll unspools, allowing the dunnage conversion machine to smoothly withdraw the raw sheets of stock material.

In conclusion, an exemplary embodiment of this assembly includes a cylinder having an opening extending through a side of the cylinder, and a passage along a length of the cylinder configured to receive the spindle. The assembly further includes a lever, positioned on the cylinder, movable between a raised position, extending from the opening in the cylinder, and a lowered position, removed from the raised position. Moreover, the assembly includes a biasing mechanism, to bias the lever to the raised position. In summary, an exemplary roll lock assembly for securing on a spindle a roll of packaging material having a hollow core, the roll lock assembly comprising: a cylinder (111 ) including an opening (114) extending partially through a side of the cylinder, and a passage (130) along a longitudinal axis of the cylinder that is configured to receive the spindle; a lever (112), disposed in the opening of the cylinder, movable between a raised position that extends proud of the opening in the cylinder, and a lowered position that is substantially flush with the cylinder; and a biasing mechanism (116), to bias the lever to the raised position.

Although the invention has been shown and described with respect to a certain embodiment or embodiments, it is obvious that equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings. In particular regard to the various functions performed by the above described elements (components, assemblies, devices, compositions, etc.), the terms (including a reference to a “means”) used to describe such elements are intended to correspond, unless otherwise indicated, to any element which performs the specified function of the described element (i.e., that is functionally equivalent), even though not structurally equivalent to the disclosed structure that 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 or more 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

Claims We claim:

1 . A roll lock assembly for securing on a spindle a roll of packaging material having a hollow core, the roll lock assembly comprising: a cylinder (111 ) including an opening (114) extending partially through a side of the cylinder, and a passage (130) along a longitudinal axis of the cylinder that is configured to receive the spindle; a lever (112), disposed in the opening of the cylinder, movable between a raised position that extends proud of the opening in the cylinder, and a lowered position that is substantially flush with the cylinder; and a biasing mechanism (116), to bias the lever to the raised position.

2. The roll lock assembly of claim 1 , wherein the cylinder has a housing compartment (117) configured to receive the biasing mechanism.

3. The roll lock assembly of claim 2, wherein the housing component configured to receive the biasing mechanism is located inside of the opening of the cylinder.

4. The roll lock assembly of claim 1 or any of claims 1 to 3, wherein the cylinder is configured to have a compartment designed to receive the lever.

5. The roll lock assembly of claim 1 , wherein the opening extending through the side of the cylinder is trough shaped.

6. The roll lock assembly of claim 1 or any of claims 1 -5, wherein the cylinder has a diameter that is less than or equal to a diameter of the spindle to which the roll lock assembly is configured to attach.

7. The roll lock assembly of claim 1 , wherein the lever has a top surface, and the cylinder has a bottom point and while the lever is in the lowered position, a distance between the top surface of the lever and the bottom point of the cylinder is less than a diameter of the hollow core of the roll of packaging material.

8. The roll lock assembly of claim 1 or claim 7, wherein the lever’s top surface is inside the opening of the cylinder, while the lever is in the lowered position.

9. The roll lock assembly of claim 1 , wherein the top surface of the lever is flat.

10. The roll lock assembly of claim 1 or any of claims 1 -9, wherein the lever further comprises a first opening (118) that cooperates with a first pin (218) extending into the first opening, where the first pin is attached to the cylinder and defines an axis about which the lever can rotate.

11 . The roll lock assembly of claim 1 or any of claims 1 -10, wherein the lever further comprises a second opening (120) that cooperates with a second pin (220) extending into the second opening, connected to the cylinder, to define an angular range of motion of the lever.

12. The roll lock assembly of claim 1 , in combination with the roll of packaging material, wherein when in the raised position, the lever engages a surface of the roll of packaging material.

13. The roll lock assembly of claim 1 or 12, in combination with the roll of packaging material, wherein the lever engages an outer surface of the hollow core.

14. The roll lock assembly of claim 1 , or any of claims 1 -13, wherein the lever is configured to have a blunt tip at a distal end.

15. The roll lock assembly of claim 1 , wherein the biasing mechanism is elastic.

16. The roll lock assembly of claim 1 or 15, wherein the biasing mechanism is a spring.

17. The roll lock assembly of claim 1 , wherein the passage (130) along the length of the cylinder has an internal surface (131 ), configured to secure the assembly to the spindle.

18. A method of securing on a spindle a roll of packaging material having a hollow core, the method comprising: providing a cylinder having an opening extending partially through a side of the cylinder, and a passage along a longitudinal axis of the cylinder that is configured to receive the spindle; providing a lever, disposed in the opening of the cylinder, movable between a raised position that extends proud of the opening in the cylinder, and a lowered position that is substantially flush with the cylinder; and providing a biasing mechanism, to bias the lever to the raised position.