DK179062B1

DK179062B1 - A roller brake system

Info

Publication number: DK179062B1
Application number: DKPA200900922A
Authority: DK
Inventors: Palle F Thomsen
Original assignee: Kvk Hydra Klov As
Priority date: 2009-08-12
Filing date: 2009-08-12
Publication date: 2017-10-02
Also published as: DK200900922A

Abstract

There is provided a roller brake system comprising an inner annular member 1 connected to a load shaft, an outer annular member 2 constituting a housing of the system, at least one wedge-shaped space at a position along a circumferential direction between said inner annular member 1 and said outer annular member 2, each said wedge-shaped space having a wider side and a narrower side, said narrower side being narrowing in the ends along said circumferential direction, a drive member 3 connectable to a crankshaft of an engine, said drive member coupled to the inner annular member and provided with protrusions that divide the wedge-shaped space into two sub-spaces each including a roller 4a or 4b, rollers 4a and 4b, and coil members 5 as elastic members to eject rollers from the ends of the the wedge-shaped space.

Description

A roller brake system

FIELD OF THE INVENTION

This invention relates to a braking system having a load limiting mechanism for a hoist. Specifically the present invention relates to a brake system of a type employing rollers. This brake system is built into a pulley or shaft mounted to auxiliary machinery driven by a crankshaft of an engine.

BACKGROUND OF THE INVENTION

Hoists equipped with load limiting mechanism, and with load brakes, are naturally quite old in the art. A particularly effective type of brake mechanism utilized in the hoist art is known as a Weston brake, and one such mechanism is found in the Schroeder U.S. Pat. No. 2,244,221. This mechanism embodies broadly a ratcheted brake disk that is adapted for free rotation in one direction, corresponding to a lift direction, but is held by a cooperating ratchet pawl against movement in a reverse direction. The load lifting and annular member means, including an axially movable driving element, are locked to the ratcheted disk by friction under certain conditions, as is well understood in the art, to hold the load against lannular member movement. Release from the ratcheted disk is easily effected by operating the load lifting means in an annular member direction. A load brake similar to that shown by Schroeder is shown in the Juergens U.S. Pat. No. 1,867,409. There, the disk equivalent to the ratcheted disk of Schroeder, is held by a series of detents against rotation in a direction corresponding to the annular member of the load, and functions therefore just as does the Schroeder ratcheted disk to control the load. As a further detail, in Juergens a cam mechanism is utilized to an annular member about locking of the load lifting mechanism to the ratcheted disk, whereas in Schroeder a cam screw is utilized for the particular purpose.

Many means have been developed in the prior art for preventing overload, and one mechanism that has been suggested is a friction clutch such as found in the Robins et al. U.S. Pat. No. 2,501,096. Since a hoist must be designed to occupy as little space as possible, it is obvious that a friction clutch such as is found in Robins et al. is not entirely satisfactory. Thus, it is obvious that the friction disks utilized by Robins must be assembled relatively to one another and be retained in assembled position and that this requires space and a considerable number of parts. A conventional one-way clutch has an inner annular member and an outer annular member disposed inside and outside each other in a diameter direction and concentrically with each other. Wedge-shaped spaces each with a gap in a diameter direction narrowing in one direction in a circumferential direction are formed at some positions on a circumference in a gap through which both the annular bodies face each other. A roller is individually disposed in each wedge-shaped space. Between both the annular bodies, a cage having pockets extending to open inside and outside in a diameter direction at positions in phase with the wedge-shaped spaces is provided. Each roller is individually housed by each corresponding pocket. An elastic member is housed by each pocket. Each roller is elastically biased by each elastic member toward a narrower side (lock side) in one direction in the circumferential direction in the wedge-shaped space. The wedge-shaped spaces are formed by providing cam faces to one of the annular bodies (an outer peripheral face of the inner annular member or an inner peripheral face of the outer annular member) and a wedge angle of the wedge-shaped space is generally set at 9° to 11°. The wedge angle is an angle at which two tangents intersect each other, one of the tangents being a tangent at a point of contact at which the roller contacts the outer peripheral face of the inner annular member and the other of the tangents being a tangent at a point of contact at which the roller contacts the inner peripheral face of the outer annular member when the roller roils to the lock side.

In the above structure of the one-way clutch, when each roller roils to the narrower side in one direction in the circumferential direction of the wedge-shaped space, the clutch is brought into a lock state in which the inner annular member and the outer annular member are Integrated with each other through the rollers and rotate synchronously. When each roller roils to a wider side in the other direction in the circumferential direction of the wedge-shaped space, the clutch is brought into a free state in which the inner annular member and the outer annular member rotate with respect to each other. In this manner, depending on a position in the wedge-shaped space to which each roller roils, the clutch is switched between the lock state and the free state. In conventional clutches having the above wedge angle, a lock malfunction may occur. DE 10 2005 061 791 A1 discloses an locking mechanism system comprising an inner annular member connected to a shaft; an outer annular member constituting a housing of the system as well as more than two spaces distributed equally along a circumferential direction between the inner and outer annular members. DE 10 2005 061 791 A1 further discloses a drive member connectable to a crankshaft of an engine, said drive member is coupled to the inner annular member and it is provided with protusions that divide the spaces into two sub-spaces, each of which are adapted to include a roller. DE 10 2005 061 791 A1 additionally discloses rollers and coil springs arranged to eject rollers from the ends of a space. Meanwhile, in DE 10 2005 061 791 A1 the wedge-shaped sub-spaces are not wedge-shaped sub-spaces that are narrow in the middle of a set of wedge-shaped spaces in a circumferential direction.

It is an object of the present invention to provide an alternative locking mechanism system suitable as a roller brake system.

SUMMARY OF THE INVENTION

As a feature of the invention of this application, a brake mechanism is utilized directly with the load shaft.

It is a main object of the present invention to provide a brake system in which generation of a lock malfunction is prevented.

It is another object of the invention to provide a brake system in which a wedge angle of each wedge-shaped space is set at a proper value, switching between a lock state and a free state is made smooth, and the response property of the brake operation is improved.

Other objects, features, and advantages of the invention will become apparent from the following descriptions.

According to the invention, there is provided a brake system including an inner annular member, an outer annular member which is disposed outside the inner annular member and concentrically with the inner annular member and constitutes at least two sets of wedge-shaped spaces at some positions in a circumferential direction between the inner annular member and the outer annular member, each set of wedge-shaped space being narrow in the middle of the space in the circumferential direction, and two rollers each disposed on each side of the narrow part of the space for switching between a lock State in which half of the rollers roil to the narrower space of the wedge-shaped space to integrate both the annular bodies with each other to allow both the annular bodies to rotate synchronously and a free State in which each roller roils to a wider side of the wedge-shaped space to cancel the lock State to allow both the annular bodies to rotate with respect to each other, wherein the inner annular member and the outer annular member have a structure in which a wedge angle of each wedge-shaped space is set at 2° to 12°, preferably 2,5° to 10°, more preferably 3° to 8°, and most preferably 3,5° to 6°. The wedge angle being the angle between the tangent at the most narrow part of the space and the slope of the wedge.

If the wedge angle of the wedge-shaped space is set at the above value, an engagement position of each roller is at a position in the wedge-shaped space with the narrowest wedge angle and is relatively shallow when the roller is positioned on the narrower side of the wedge-shaped space and gaps between each roller and both the annular bodies are relatively small when the roller is positioned on the wider side of the wedge-shaped space. Therefore, the rollers move smoothly in switching between the lock State and the free State.

In a preferred embodiment of the present invention there is provided a roller brake system comprising: • an inner annular member 1 connected to a load shaft; • an outer annular member 2 constituting a housing of the system; • at least two sets of wedge-shaped spaces, wherein the outer annular member 2 is disposed outside the inner annular member 1 and concentrically with the inner annular member 1 establishing said at least two sets of wedge-shaped spaces at positions in a circumferential direction between the inner annular member 1 and the outer annular member 2, each set of wedge-shaped spaces being narrow in the middle of the set of wedge-shaped spaces in the circumferential direction, • a drive member 3 connectable to a crankshaft of an engine, said drive member coupled to the inner annular member and provided with protrusions that divide the set of wedge-shaped spaces into two sub-spaces each including a roller 4a or 4b; • rollers 4a and 4b, wherein two rollers are each disposed on each side of the narrow part of said set of wedge-shaped spaces for switching between: o a lock state in which half of the rollers roil to the narrower side of their wedge-shaped sub-space to integrate both annular bodies with each other to allow both the annular bodies to rotate synchronously, and o a free State in which each roller roils to a wider side of its wedge-shaped sub-space to cancel the lock state to allow both annular bodies to rotate with respect to each other; • elastic members 5 to eject rollers from the ends of the wedge-shaped spaces wherein the outer annular member 2 as well as adjacent end cabs and/or bearings establish a closed lubricatable environment.

In a particularly preferred embodiment the inner annular member and the outer annular member have a structure in which a wedge angle of each wedge-shaped sub-space is set at 2° to 12°.

It is preferred that the inner and outer annular members are made from Steel.

In order to obtain a stable construction it is preferred that the roller brake system of the present invention involves two wedge-shaped spaces with two sets of rollers.

It is preferred that the inner annular member 1 constitutes an end of a load shaft, and that the drive member 3 constitutes an end of a crankshaft of an engine.

BRIEF DESCRIPTION OF THE DRAWING

These and other objects as well as advantages of the invention will become clear by the following description of preferred embodiments of the invention with reference to the accompanying drawing. FIG. 1 is a sectional side view of the brake system according to a preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The brake system according to a preferred embodiment of the present invention will be described below with reference to FIG. 1.

The brake system has, as its components, an inner annular member 1 connected to a load shaft, an outer annular member 2, a drive member 3 connected to a crankshaft of an engine, said drive member coupled to the inner annular member, rollers 4a and 4b, and coil members 5 as elastic members to eject rollers from their seat. The drive member is equipped with protrusions that divide the wedge-shaped space into two sub-spaces each including a roller 4a or 4b. The roller roils to a narrower side (lock side) or a wider side (free side) in the wedge-shaped space according to a rotation difference between the inner annular member 1 and the outer annular member 2.

If the roller 4a roils to the lock side, the inner annular member 1 and the outer annular member 2 are brought into a lock state in which the inner annular member 1 and the outer annular member 2 are Integrated with each other through the roller 4a.

If the roller 4a roils to the free side, the lock state of the inner annular member 1 and the outer annular member 2 is cancelled and the inner annular member 1 and the outer annular member 2 are brought into a free state in which the inner annular member 1 and the outer annular member 2 rotate with respect to each other. In this manner, the inner and outer annular members are switched between the lock state and the free state depending on the position to which the roller 4a roils. This applies oppositely to roller 4b.

Claims

A roller braking system comprising: • an inner annular component 1 connected to a load shaft; An outer annular component 2 constituting the housing of the system; At least two sets of wedge-shaped compartments in which the outer annular component 2 is located outside the inner annular component 1 and concentric with the inner annular component 1, wherein said at least two sets of wedge-shaped compartments are established between the inner annular component 1 and the outer annular component 2, wherein each set of wedge-shaped compartments is narrow in the center in the circumferential direction; subspaces each having a roll 4a or 4b; Rollers 4a and 4b, wherein a roller is positioned on each side of the narrow portion of said set of wedge-shaped compartments for switching between: • a locking state in which half of the rollers roll to the narrower side of their wedge-shaped subspace for integrating both annular components with one another to allow both annular components to rotate synchronously, and a free state, with each roller rolling to a wider side of the wedge-shaped subspace to unlock the locking state to allow both annular components rotate relative to each other; Elastic components 5 for pushing rollers from the ends of the wedge-shaped space; wherein the outer annular component 2 as well as adjacent end piece and / or bearings establish a closed lubricable environment.

A roller braking system according to claim 1, wherein the inner annular component and the outer annular component have a structure wherein a wedge angle of each wedge-shaped subspace is from 2 ° to 12 °.

A roller brake system according to claim 1 or 2, wherein the inner and outer annular components are made of steel.

A roller braking system according to any one of the preceding claims, wherein the inner annular component 1 is an end of a load shaft.

A roller braking system according to any one of the preceding claims, wherein the drive component 3 constitutes an end of a crankshaft in a motor.