DK179809B1

DK179809B1 - Bar feeder

Info

Publication number: DK179809B1
Application number: DKPA201800013A
Authority: DK
Inventors: Holm Knudsen Per
Original assignee: Universal Bar Feeder Aps
Priority date: 2018-01-11
Filing date: 2018-01-11
Publication date: 2019-07-01
Also published as: EP3737521A1; DK201800013A1; WO2019137676A1

Abstract

The present invention relates to a bar feeder for feeding elongated bars to a working machine. The bar feeder comprises a) a plurality of support units positioned in parallel, and spaced apart, along the length of the bar feeder; each support unit comprising a receiving groove with the opening facing the front side of the bar feeder; wherein all receiving grooves are configured to jointly receive an elongatedbar sideways; b) at least three elongated rods or tubes that extend along the length of the bar feeder, and each positioned equidistant from the two closest of their neighbouring elongated rods or tubes; wherein the elongated rods or tubes encircle the bottom of the receiving grooves; wherein each elongated rod or tube comprises a plurality of wheel assemblies, each wheel assembly comprising a wheel, and a wheel shaft; wherein the wheel shaft is connected to the elongated rods or tubes;and c) means adapted for rotating the elongated rods or tubes around their longitudinal axis, such that the wheels may move between a retracted position and a forwarded position.

Description

Technical field of the invention

The present invention relates to bar feeders.

Background of the invention

A considerable segment of the metalworking manufacturing industry pertains to turning. In this process, a metalworking lathe spins bars of various lengths and diameters at the appropriate revolutions per minute while cutting the workpiece with a tool to the specified shape or diameter. Metalworking lathes are driven mechanically by cams and other mechanical devices, or electronically with the use of CNC (computer numeric control) and may be configured with a sliding or fixed headstock (spindle).

A bar feeder pushes a bar of selected diameter into the workspace of the lathe for part production. After the part is worked to completion and cut off, the lathe chuck automatically opens, signalling the bar feeder to push the bar material to the next working length and the cycle thus repeats.

In simplest form, a bar feeder requires an operator to manually reload the next bar of material for working. Taking automation one step further, a device called a magazine bar loader not only feeds the bar material into the lathe, but also automatically reloads the next bar length providing a continuous supply of material to the lathe without operator intervention.

The metalworking manufacturing industry want to run their bar machines as fast as possible, typically at speeds in excess of 5,000 to 10,000 rpm, to achieve high production rates. Although a certain amount of the material is supported within the headstock or spindle of the lathe, the remainder of the material must be supported in the bar feeder. As the rotating speed of a bar increases, the remaining part of the bar tends to whip and vibrate in the bar feeder, adversely affecting machining results, and machine noise is elevated .

There is a direct correlation between bar straightness and bar vibration experienced in the bar feeder. Steel manufacturers have responded to this need by refining their processes to provide straighter material to their turning manufacturing customers, but non-ferrous materials are usually extruded as opposed to drawn (as most steels are) and the straightness cannot be as closely controlled. In addition, even if the bars are straight when it leaves the manufacturer, it may be damaged in handling before it reaches the bar feeder. Hence, vibration dampening in bar feeders remains a big issue.

For precision production operations, vibration dampening is generally accomplished by hydrodynamic suspension of the bar in a guide channel mechanism with a heavy oil to dampen bar whip and vibration. This is generally effective until the mass/diameter of the material overcomes the effective use of hydrodynamic suspension, or until the bar straightness is out of the operational condition for this method of vibration dampening. Hydrodynamic suspension in a bar feeding device is provided by a simple recirculating, non-pressurized flow of oil between the outside diameter of the spinning bar and the inside diameter of the guide channel to allow the bar to find its natural line of least resistance, which in a straight bar, is the centre of the channel. This allows the bar of whatever length and diameter to spin at the required rounds per minute silently and with no vibration. The oil should be of a viscosity to provide adequate hydrodynamic suspension, but the bar should spin relatively free of the oil in the transition area between the bar feeder and the lathe so as not to introduce tramp oil into the lathe coolant. The latter requirement prevents the use of heavier viscosity oils that may provide better vibration dampening qualities. When the mass or diameter of the bar or the lack of straightness overcome the hydrodynamic suspension of the bar feeding device the lathe RPM must be reduced, compromising productivity, or quality is compromised.

Furthermore, the hydrodynamic suspension technique requires that the bars are loaded end first into the end of the guide channel, which requires a lot of space available for such bar feeders.

CN201030440 discloses an automatic bar feeding device composed of a material rack 1, a bar material damping unit 2, an auxiliary bar material restraining mechanism 3, and a feeding mechanism 4. The number of bar material damping units can be increased or decreased according to the length and diameter range of the bar. The bar 9 is located in an inscribed circle composed of three rollers 28 of each bar material damping unit 2. This type of bar material damping unit has problems with centring the bar material in front of the inlet of the working machine.

It is therefore desirable to provide a bar feeder, which can eliminate, or at least alleviate, the above problems.

Description of the invention

A first aspect relates to a bar feeder for feeding elongated bars to a working machine, the bar feeder comprising:

- a plurality of support units positioned in parallel, and spaced apart, along the length of the bar feeder; each support unit comprising a receiving groove with the opening facing the front side of the bar feeder; wherein all receiving grooves are configured to jointly receive an elongated bar sideways;

- at least three elongated rods or tubes that extend along the length of the bar feeder, and each positioned equidistant from the two closest of their neighbouring elongated rods or tubes; wherein the elongated rods or tubes encircle the bottom of the receiving grooves; wherein each elongated rod or tube comprises a plurality of wheel assemblies, each wheel assembly comprising a wheel, and a wheel shaft; wherein the wheel shaft is connected to the elongated rods or tubes; and

- means adapted for rotating the elongated rods or tubes around their longitudinal axis, such that the wheels may move between a retracted position and a forwarded position.

The bar feeder of the present invention is a mechanical solution, completely avoiding the use of oil. Hence, there will be no oil contamination of the produced parts; and oil waste is generally avoided, as no oil needs to be replaced. Furthermore, the bar feeder may handle elongate bars of different diameters, as there is no size limiting guide channel.

The support units are positioned in parallel, and spaced apart, along the length of the bar feeder. They may be a part of the chassis of the bar feeder, thereby contributing to the stability of the bar feeder. Each support unit comprises a receiving groove with the opening facing the front side of the bar feeder. A bar, e.g. from a bar stock, is loaded sideways into the bar feeder. Hence, the front of the bar feeder is its side, rather than the end facing away from the working machine, as is the case with conventional bar feeders on the market. The support units are preferably configured as a plate to provide as much space as possible for the wheel assemblies to work on the bar positioned within the bar feeder. All receiving grooves are configured to jointly receive an elongated bar sideways.

At least three elongated rods or tubes that extend along the length of the bar feeder, and each positioned equidistant from the two closest of their neighbouring elongated rods or tubes. This configuration is important for the bar feeder to centre the bar in front of the inlet of the working machine (e.g. a metalworking lathe). More than three elongated rods or tubes may be used, but is in crucial for the centring process that they are positioned equidistant from the two closest of their neighbouring elongated rods or tubes. If three elongated rods or tubes are used, a transverse cross-section of the bar feeder will reveal that the elongated rods or tubes define the corners of an equilateral triangle. If four elongated rods or tubes are used, a transverse crosssection of the bar feeder will reveal that the elongated rods or tubes define the corners of an equilateral square. If five elongated rods or tubes are used, a transverse cross-section of the bar feeder will reveal that the elongated rods or tubes define the corners of an equilateral pentagon, and so forth. Each elongated rod or tube comprises a plurality of wheel assemblies, each wheel assembly comprises a wheel, and a wheel shaft. The wheel shaft is connected to the elongated rods or tubes. The elongated rods or tubes encircle the bottom of the receiving grooves, i.e. the place where the loaded bar rests in the receiving grooves. This configuration is necessary for the wheel assemblies to raise the bar from its resting position at the bottom face of the bottom of the receiving grooves. Hence, when the wheels are in a forwarded position, the bar is grabbed between the wheels and raised from its resting position at the bottom face of the bottom of the receiving grooves. Thereby, the bar will not be rotated when in contact with the receiving groove walls, eliminating possible tear of the receiving grooves and the bar.

In one or more embodiments, the elongated rods or tubes are adapted to synchronically move around their longitudinal axis. In one or more embodiments, the elongated rods or tubes are connected by coupling rods adapted for synchronically moving said elongated rods or tubes around their longitudinal axis.

In one or more embodiments, the wheels are made of or coated with an elastomeric material, such as rubber. This material is suitable for dampening the vibrations of the elongated bar.

In one or more embodiments, the wheels are adapted to rotate freely in both directions. This configuration allows the working machine to rotate the bar in both directions, as the wheels will passively follow the direction of rotation.

In one or more embodiments, the wheel assemblies are connected to the elongated rods or tubes such that the wheels in the forwarded position are positioned perpendicular to the length of the of bar feeder. Otherwise, the wheels will not turn when engaged with a bar rotated by the working machine.

In one or more embodiments, the elongated rods or tubes are rollably or rotatably engaged with the support units. A bearing may be used for this engagement. This configuration allows for the rods to contribute to the stability of the bar feeder.

In one or more embodiments, at least one of the elongated rods or tubes are rollably or rotatably engaged with the support units below the bottom wall of the receiving grooves. A bearing may be used for this engagement.

In one or more embodiments, at least one of the elongated rods or tubes are positioned below the bottom wall of the receiving grooves.

In one or more embodiments, the wheel assemblies connected to the lowest positioned elongated rod or tube, relative to the bottom of the bar feeder, are configured such that the wheels in the retracted position are positioned below the bottom wall of the receiving grooves, and in the forwarded position are positioned above the bottom wall of the receiving grooves. This configuration is suitable for the wheel assemblies to raise the bar from its resting position at the bottom face of the bottom of the receiving grooves. Hence, when the wheels are in a forwarded position, the bar is grabbed between the wheels and raised from its resting position at the bottom face of the bottom of the receiving grooves. Thereby, the bar will not be rotated when in contact with the receiving groove walls, eliminating possible tear of the receiving grooves and the bar.

In one or more embodiments, the receiving grooves slopes down towards the bottom of the bar feeder. This configuration allows for an easier loading of the bar into the bar feeder.

In one or more embodiments, the bar feeder further comprises means adapted for rotating the elongated rods or tubes around their longitudinal axis, such that the wheels may move from a forwarded position to a partly forwarded position.

In one or more embodiments, the bar feeder further comprises a storage unit or rack adapted for receiving a stack of bars. The storage unit or rack may be coupled to the front side of the bar feeder, and/or may comprise means adapted for positioning a single bar from the stack of bars into the bar feeder.

In one or more embodiments, the bar feeder is modular. The bar feeder may be adapted to be built in different lengths by inserting or removing middle segment units between a first end segment comprising the means adapted for rotating the elongated rods or tubes around their longitudinal axis, such that the wheels may move between a retracted position and a forwarded position; and a second end segment comprising the outlet.

In one or more embodiments, the bar feeder comprises means adapted for pulling a bar in the longitudinal direction of the bar feeder. In one embodiment, such means may be a pair of feeder wheels adapted for moving between a retracted position and a forwarded position, and positioned parallel to the length of the of bar feeder.

In one or more embodiments, the pulling means comprises a pair of feeder wheels adapted for moving between a retracted position and a forwarded position.

As used in the specification and the appended claims, the singular forms a, an, and the include plural referents unless the context clearly dictates otherwise. Ranges may be expressed herein as from about or approximately one particular value and/or to about or approximately another particular value. When such a range is expressed, another embodiment includes from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent about, it will be understood that the particular value forms another embodiment.

It should be noted that embodiments and features described in the context of one of the aspects of the present invention also apply to the other aspects of the invention.

Brief description of the figures

Figure 1 shows a perspective view of a bar feeder in accordance with various embodiments of the invention;

Figure 2 shows a closeup view of a part of Figure 1;

Figure 3 shows the outlet of a bar feeder in accordance with various embodiments of the invention; and

Figure 4 shows an end view of a bar feeder in accordance with various embodiments of the invention.

Detailed description of the invention

Figure 1 shows a bar feeder 100 for feeding elongated bars to a working machine. The bar feeder 100 comprises seven support units 200 positioned in parallel, and spaced apart, along the length of the bar feeder 100. Each support unit 200 comprises a receiving groove 210 with the opening 212 facing the front side of the bar feeder 100. All receiving grooves 210 are configured to jointly receive an elongated bar sideways.

Three elongated rods or tubes 300 extend along the length of the bar feeder 100, and are each positioned equidistant from one another. The elongated rods or tubes 300 encircle the bottom of the receiving grooves 210, and each comprises a plurality of wheel assemblies 310. Each wheel assembly 310 comprises a wheel 312, and a wheel shaft 314. The wheel shaft 314 is connected to the elongated rods or tubes 300.

The bar feeder 100 also comprises means 400 adapted for rotating the elongated rods or tubes 300 around their longitudinal axis, such that the wheels 312 may move between a retracted position and a forwarded position. The elongated rods or tubes 300 synchronically move around their longitudinal axis as they are connected by coupling rods 410 (one of them shown in figure 4).

Figure 2 shows a closeup view of the end part of Figure 1, that functions as an outlet for the bar being fed to the working machine (not shown). Two feeder wheels 600 adapted for feeding the bar to the working machine is shown in a retracted position. The feeder wheels are moved towards each other to engage with the bar, when the bar needs to be advanced into the working machine. Figure 3 shows an end view of the outlet of the bar feeder. The upper feeder wheel 600 can be seen, but the lower feeder wheel is positioned behind a wheel 312 of a wheel assembly. To allow the bar to be advanced by the feeder wheels, the wheel assemblies must be retracted slightly from engagement with the bar, but still relatively close to the bar to retain the centred position relative to an inlet of the working machine. This operation is performed by means 500 (Figure 4) adapted for rotating the elongated rods or tubes 300 around their longitudinal axis, such that the wheels 312 may move from a forwarded position to a partly forwarded position. The means are here shown as a cylinder performing work on a push plate 420.

The bar feeder also comprises a storage unit or rack 700 adapted for receiving a stack of bars. The storage unit or rack is coupled to the front side of the bar feeder.

References

100 Bar feeder

200 Support unit

210 Receiving groove

212 Opening

300 Elongated rod or tube

310 Wheel assembly

312 Wheel

314 Wheel shaft

400 Means adapted for rotating the elongated rods or tubes around their longitudinal axis, such that the wheels may move between a retracted position and a forwarded position

410 Coupling rod

420 Push plate

500 Means adapted for rotating the elongated rods or tubes around their longitudinal axis, such that the wheels may move from a forwarded position to a partly forwarded position

600 Feeder wheel

700 Storage unit or rack

Claims

Patent claims

A rod feed system (100) for feeding elongate rods to a processing machine, the rod feed system (100) comprising:

a plurality of support units (200) located parallel, and at intervals, along the length of the rod feed system (100); each support unit (200) comprising a receiving groove (210) with the opening (212) facing the front of the rod feed system (100); wherein all receiving grooves (210) are adapted to receive together an elongate rod laterally;

characterized in that the bar feed system (100) further comprises:

- at least three elongate rods or tubes (300) extending along the length of the rod feed system (100), each located equidistant from the two nearest of the adjacent elongate rods or tubes (300); wherein the elongate rods or tubes (300) enclose the bottom of the receiving grooves (210); wherein each elongate rod or tube (300) comprises a plurality of wheel assemblies (310), each wheel assembly (310) comprising a wheel (312) and a wheel axle (314); wherein the wheel axle (314) is connected to the elongate rods or tubes (300); and

means (400) adapted to rotate the elongate rods or tubes (300) about their longitudinal axis so that the wheels (312) can move between a retracted position and an advanced position.

The rod feed system (100) of claim 1, wherein the wheel assemblies (310) are connected to the elongate rods or tubes (300) so that the wheels (312) in the advanced position are positioned perpendicular to the length of the rod feed system (100).

A rod feed system (100) according to any one of claims 1-2, further comprising means (500) adapted to rotate the elongate rods or tubes (300) about their longitudinal axis so that the wheels (312) can move from an advanced position to a partially advanced position.

A rod feed system (100) according to any one of claims 1-3, further comprising pulling means adapted to pull a rod located inside the receiving grooves (210) in the longitudinal direction of the rod feed system.

A bar feed system (100) according to claim 4, wherein the traction means comprises a pair of feed wheels (600) adapted to move between a retracted position and an advanced position and located parallel to the length of the bar feed system: (100).

A rod feed system (100) according to any one of claims 1-5, wherein the elongate rods or tubes (300) are rotatably connected to the support units (200).

A rod feed system (100) according to claim 6, wherein at least one or one of the elongate rods or tubes (300) is rotatably connected to the support units (200) below the bottom wall of the receiving grooves (210).

A rod feed system (100) according to any one of claims 1-7, wherein at least one or one of the elongate rods or tubes (300) is located below the bottom wall of the receiving grooves (210).

A rod feed system (100) according to any one of claims 1-8, wherein the wheel assemblies (310) connected to the lowest positioned elongate rod or the lowest positioned elongate tube (300) relative to the bottom of the rod feed system (100) ), is adapted so that the wheels (312) in the retracted position are located below the bottom wall of the receiving grooves (210), and in the projected position are located above the bottom wall of the receiving grooves (210).

A rod feed system (100) according to any one of claims 1-9, wherein the receiving grooves (210) slope down towards the bottom of the rod feed system (100).