DE102010019883B4 - gathering wheel - Google Patents

Abstract

Raffrad (1) for axial Zusammenraffen a hose material (11) having a plurality of circumferentially by tooth spaces (2) spaced Raffzähnen (3), each Raffzahn (3) in the intended direction of rotation (U) front and rear tooth flank (4a, 4b ), characterized in that the front tooth flanks (4a) are each formed with a positive angle of attack (α) relative to the intended direction of rotation (U).

Description

The invention relates to a Raffrad for axial Zusammenraffen a hose material having a plurality of spaced apart in the circumferential direction by tooth gaps Raffzähnen, each Raffzahn has a front and rear tooth flank provided in the intended direction of rotation.

Such gathering wheels are usually used on a gathering head, which surrounds a central guide pin, on which the tube material to be gathered is fed. Under tube material, for example, intestines are understood in particular artificial casings for sausage production. In addition, the tubing is suitable for holding other liquids, powders or granules.

A rotating tie head for axial gathering of tubular casing material is for example from DE 40 09 193 A1 known. The Raffräder arranged on the Raffkopf have on the periphery flat paddle-shaped teeth which push together the supplied on a shirring mandrel in the axial direction.

A similar state of the art forms the DE 31 40 583 A1 with at least two distributed on the mandrel circumference attacking, synchronously driven Raffrädern that are provided with wing-like thin-walled teeth. The teeth are inclined in the direction of rotation with their outer end against their located in the transition region to a cylindrical main body tooth base backwards and therefore have a negative angle of attack.

The main disadvantage of the known from the prior art Raffräder lies in the relatively low compression of the shirring leaving hose material. This results, in particular, from the fact that the pushed-together tube material is not deposited in even folds, which has a negative effect, especially in collagen intestines, when they are watered and not all wrinkles are wetted by the water. In the area of the dry areas then often arise tears.

For this reason, the invention has the object to provide a Raffrad which allows a more uniform storage of the tubing and thus pushes together more tubing per unit length.

The object is achieved with a Raffrad, in which the front tooth flanks are formed with respect to the intended direction of rotation in each case with a positive angle of attack. The angle of attack results from the inclination of the front tooth flank with respect to the radius of the Raffrades drum-like in the axial direction. As a result, in the intended direction of rotation, the radially outer end of the front tooth flank projects in front of the inner end, as a result of which the hose material is particularly well grasped and pulled in. Only when detaching the hose material from the shirring tooth this is additionally pushed together in its axial direction. The known from the prior art Raffräder put the tubing exclusively by squeezing in the axial direction. The laying of the tube material takes place when using inventive Raffräder in the axial direction conically overlapping, so that an extremely compact and orderly gathering of the tubing is possible. On a given length, this can accommodate between 20 to 50% more tubing.

Advantageously, the positive angle of attack between 1 ° to 15 °, more preferably 7 ° to 12 °. In this angular range there is an optimal storage and compression of the tubing.

It has proved to be advantageous if between the tooth flanks an outer lateral surface portion is arranged, wherein preferably the front tooth flank and the adjacent outer lateral surface portion form a shirring edge, which comes into operative engagement with the tube material to be gathered. After bringing the hose material with the shirring edge this comes to rest on the outer surface.

The shirring edge should extend at an angle <90 ° between the outer lateral surface portion and the rectilinear, under a positive angle of attack extending front tooth flank.

Conveniently, the front and / or rear tooth flanks are inclined in the axial direction at a transverse angle, which should be 15 ° to 35 °, particularly preferably 20 ° to 25 ° to the axial direction of the Raffrades. Known Raffräder often have aligned in the axial direction tooth flanks with a transverse angle of 0 °. Because of the front tooth flank running under the transverse angle, the latter does not grip the hose material at the same time, but with its forward section in the direction of rotation. The relative to the tube material to be gathered in the axial direction of the Raffrades previous portion of the front tooth flank then successively in contact with the tubing and lays it off.

A rear tooth flank, also running at a transverse angle, ensures a constant Width of the tooth gap following in the direction of rotation. This favors a nestling of the tubing in the tooth gap and thereby brings the tubing below a level of the subsequent tooth flank, which can then attack particularly effective on the tubing.

Advantageously, the outer lateral surface sections each have a concave recess extending in the circumferential direction. The concave recess is adapted to the diameter of a guide pin on which the tubing is usually supplied to the Raffrädern when inflated. The distance of the concave recess to the guide mandrel in the radial direction is preferably 2 mm to 3 mm.

Conveniently, the outer lateral surface sections each pass with a rounding in the rear tooth flank, wherein the rounding may have a radius> 10 mm. The rounding favors spreading of the tubing into the tooth gap following the operative engagement tooth. As a result, the following in the direction of rotation Raffzahn attack particularly effective on the tubing.

According to a particularly preferred embodiment, each of the outer lateral surface sections is formed in the circumferential direction in the form of a circular arc section. The contour corresponding to a circular arc section allows on the one hand effective engagement of the shirring edge to the hose material and on the other hand, a favorable spreading of the hose material in the subsequent tooth gap. Due to the rounded outer surface also local strains or damage to be ruffled tubing are minimized.

Advantageously, the Raffrad is made as a homogeneous component of polyoxymethylene. Polyoxymethylene (abbreviated POM, also called polyacetal or polyformaldehyde) is a high molecular weight thermoplastic. Due to its high rigidity, low coefficient of friction and excellent dimensional stability as well as thermal stability, POM is used as engineering plastic, especially for precision parts. POM is characterized by high strength, hardness and stiffness in a wide temperature range. It retains its high toughness down to -40 ° C, has high abrasion resistance, a low coefficient of friction, high heat resistance, good electrical and dielectric properties, and low water absorption.

Another advantage of the plastic in question lies in the particularly quiet running properties of Roman wheels, which comes particularly to fruition when each Raffrad and also necessary for the drive toothing of each Raffrades are made of polyoxymethylene. The teeth are preferably screwed for manufacturing reasons as a separately manufactured component with the homogeneously manufactured Raffrad to a one-piece unit.

By using the material polyoxymethylene in the area of the toothing of each Raffrades can be dispensed with a lubrication. This has led to black spots on the tubing in older Raffrädern which often have a main body with a formed thereon drive teeth made of metal. The black dots consist in particular of deposited lubricant and represent a significant impairment of the shirred and intended primarily for receiving food hose material.

Preferably, the width of the tooth gap in the circumferential direction corresponds to the width of a tooth base. As a result, as close as possible shirring of the tube material due to a sufficient number of Raffzähnen as well as a nestling of the tubing is achieved in sufficiently sized tooth gaps.

Expediently, each tooth gap comprises an inner circumferential surface section running spirally in the axial direction. The term "helical" is understood to mean a section of a complete spiral revolution. The inner lateral surface portion is bounded on both sides in the circumferential direction by a likewise spirally extending front or rear tooth flank.

The tooth gap defined by the inner lateral surface section and the front and rear tooth flanks can advantageously be designed with a rectangular cross-sectional area and offset in the radial direction eccentrically with respect to the central axis. Consequently, over the entire course of the tooth gap, the front and possibly also the rear tooth flank are perpendicular to the inner circumferential surface. This embodiment results from the manufacturing process in which a vertical cylindrical raw body of the later Raffrades and a horizontally oriented milling head are moved laterally to each other, so that the milling head is eccentrically in front of an axial end of the green body and is recognized there. Subsequently, the milling head passes through the green body with a simultaneous rotational movement. Decisive here is the relative movement of the milling head relative to the green body, either the milling head can be moved or the green body or both to each other.

The invention can also be realized on a gathering head, which comprises a plurality of gathering wheels, which are arranged around a central guide pin, on which the tube material to be gathered is pushed and the shirring teeth of adjacent reamer wheels come into operative engagement with the tube material in succession.

Advantageously, the shirring edges of adjacent shirring wheels in the axial direction of the guide pin spiral together form a closed spiral rotation and thus a helical gait. In this embodiment, successively each of the adjacent shirring edge comes into contact with the hose material, so that this is pushed together after contacting all Raffkanten involved over its entire circumference.

It has proved to be particularly favorable when four Raffräder are provided on the shirring, the outer diameter is between 80 mm and 250 mm. This results in a homogeneous ratio of diameter of the Roman wheels and number of shin teeth.

According to a particularly preferred embodiment, one of the scraper wheels is connected to a drive device and on one side adjacent scraper wheels are each driven via a bevel gear arrangement. Thus, only one Raffrad preferably with a front-side trained pinion with the drive means in positive engagement. The torque transmitted by the drive device is transmitted on the pinion opposite end side to the adjacent Raffrad. Due to the design of the bearing axis of the adjacent Raffrades is angular, in particular at right angles, aligned with the bearing axis of the driven Raffrades. In this case, the torque should be transmitted to the adjacent Raffrad by means of a helical bevel gear. The second Raffrad driven by the first Raffrad then transmits the torque to the third Raffrad and this on optionally further Raffräder. Due to this constructive solution, the drive device only engages with one of the scraper wheels on its output side, so that summing tolerances do not have to be synchronized with the drive device. This would be the case if the last Raffrad also would be in positive engagement with the drive means and would therefore be driven.

For a better understanding of the invention will be described below with reference to a total of three figures. It show the

1 : a side view of a Raffrad;

2 : a front view of the Raffrad according to 1 and

3 : A perspective top view of a shirring with four shirring wheels.

The 1 shows a inventive Raffrad 1 in a side view with a total of five uniformly distributed over the circumference Raffzähnen 3 , Each of the shirring teeth 3 is on both sides by a tooth gap 2 to the neighboring Raffzähnen 3 spaced. The tooth gaps extend in the axial direction completely through the Raffrad 1 ,

The shirring teeth 3 have in the direction of rotation U a front tooth flank 4a and a rear tooth flank 4b on. Between the tooth flanks 4a . 4b extends an outer lateral surface portion 5 , which is curved according to its radius about the central axis Z. Through all outer lateral surface sections 5 runs in the circumferential direction a concave recess 7 , The concave recesses 7 are in terms of their shape complementary to the diameter of in 3 dot-dashed guide pin shown 12 educated. It should ideally an annulus of 2 mm to 3 mm between the guide pin 12 and the concave recesses 7 remain coaxially about the guide pin 12 an inflated tube material 11 to the Roman wheels 1 is introduced.

According to the invention, the front tooth flank 4a in the direction of rotation U inclined forward. The resulting angle of attack α is in the illustrated embodiment, 9.81 ° and allows a particularly compact shirring of the tubing 11 ,

The front tooth flank 4a goes at its distal end in the outer lateral surface portion 5 over and forms a Raffkante 6 with an angle smaller than 90 °. At the opposite, inner end of the tooth flank 4a closes an inner lateral surface section 10 at. The inner lateral surface section 10 is always in the circumferential direction at right angles to the front tooth flank 4a , In the axial direction of the Raffrades 1 tilts the inner surface 10 but tangentially with respect to the outer lateral surface sections 5 ,

The back tooth flank 4b points in the transition region to the outer lateral surface section 5 a rounding 8th on, the spreading of the tubing 11 in the tooth gap 2 supports, allowing the tubing 11 below the gathering edge 6 the following in the sense of rotation U subsequent Raffzahns 3 lies and thus particularly effective from the Raffkante 6 is detected.

In the 2 is the Raffrad invention 1 shown in a front view. It becomes clear that the front tooth flank 4a of the standing in the region of the central axis Z Raffzahns 3 due to its positive angle of attack α in the direction of rotation U before lying inner lateral surface portion 10 partially covered. The inside of the inner lateral surface portion 10 recognizable visible edge results from the travel of the milling head during the manufacturing process, the first in one direction and after complete driving through the Raffrades 1 moved back in parallel offset to it.

Both the shin teeth 3 as well as the tooth gaps 2 run in the axial direction at a transverse angle β through the Raffrad 1 and thereby form a spiral section at least the front tooth flank 4a out.

As a result, in the installed state of Raffräder 1 according to a tieback 3 a complete spiral turn 13 the front tooth flanks 4a reached. This in turn ensures that the tubing 11 stored sequentially in the circumferential direction and is therefore particularly tightly gathered.

In the circumferential direction, the width b1 corresponds to the tooth gap 2 approximately the width b2 of a tooth base 9 (please refer 1 and 2 ). The tooth base 9 lies in the radial direction approximately at the level of the inner lateral surface portion 10 ,

The in 3 Raffkopf shown comprises a total of four Roman wheels 1 whose central axis Z is in each case perpendicular and in a horizontal plane to the central axis Z of the adjacent Raffrades 1 is aligned. Every Raffrad 1 is for this purpose in two on both sides arranged bearing blocks 16a . 16b rotatably supported, each bearing block 16a . 16b as an abutment for two Roman wheels 1 can serve. Only a single Raffrad 1 is from a drive device not shown 14 driven. The torque applied thereby is on a side A by means of a bevel gear 15 on the adjacent Raffrad 1 and from there in the same way to the other Raffräder 1 transfer.

The concave recesses 7 together form a circular opening, through which concentric a dash-dotted lines indicated guide pin 12 passed through. Concentric around the guide pin 12 becomes the air inflated tubing 11 the Raffkopf fed, which after attacking the Raffkanten 6 is pushed together in its axial direction.

LIST OF REFERENCE NUMBERS

1

gathering wheel

2

gap

3

Raffzahn

4a

front tooth flank

4b

rear tooth flank

5

outer lateral surface section

6

Raffkante

7

concave recess

8th

curve

9

tooth root

10

inner lateral surface section

11

tubing

12

guide pin

13

spiral rotation

14

driving means

15

bevel gear

16a, b

bearing block

α

angle of attack

β

cross angle

A

Side adjacent Raffrad

b ₁

Wide tooth gap

b ₂

Wide tooth base

U

rotation

Z

central axis

Claims (13)

Raffle ( 1 ) for axial Zusammenraffen a hose material ( 11 ) with a plurality of tooth spaces in the circumferential direction ( 2 ) spaced shy teeth ( 3 ), with each long-haired tooth ( 3 ) one in the intended direction of rotation (U) front and rear tooth flank ( 4a . 4b ), characterized in that the front tooth flanks ( 4a ) are each formed with a positive angle of attack (α) relative to the intended direction of rotation (U). Raffle ( 1 ) according to claim 1, characterized in that the positive angle of attack (α) is between 1 ° to 15 °, particularly preferably 7 ° to 12 °. Raffle ( 1 ) according to claim 1 or 2, characterized in that between the tooth flanks ( 4a . 4b ) an outer lateral surface section ( 5 ) is arranged. Raffir according to claim 3, characterized in that the front tooth flank ( 4a ) and the outer lateral surface portion ( 5 ) a Raffkante ( 6 ), which comes into operative engagement with the tube material to be gathered. Raffir according to claim 4, characterized in that the Raffkante ( 6 ) is formed at an angle <90 °. Raffradge according to one of claims 1 to 5, characterized in that the front and / or rear tooth flanks ( 4a . 4b ) in the axial direction at a transverse angle (β) inclined. Raffradge according to claim 6, characterized in that the transverse angle (β) is 15 ° to 35 °, particularly preferably 20 ° to 25 ° to the axial direction. Raffradge according to one of claims 3 to 7, characterized in that the outer lateral surface sections ( 5 ) each with a rounding ( 8th ) in the rear tooth flank ( 4b ) pass over. Raffradge according to one of claims 1 to 8, characterized in that each tooth gap ( 2 ) an axially extending spirally inner lateral surface portion ( 10 ). Raffrad wheel according to claim 9, characterized in that the inner lateral surface section ( 10 ) and the front tooth flank ( 4a ) form an angle of 90 °. Raffradge according to one of claims 1 to 10, characterized in that the tooth gap ( 2 ) is formed offset with a rectangular cross-sectional area and in the radial direction eccentric to the central axis (Z). Raffkopf for axial shirring of tubing ( 11 ) comprising a plurality of shirring wheels ( 1 ) according to one of claims 1 to 11, which is arranged around a central guide pin ( 12 ) are arranged, on which the hose material to be gathered ( 11 ), characterized in that the shin teeth ( 3 ) of adjacent Roman wheels ( 1 ) successively with the tubing ( 11 ) come into operative engagement. Raffkopf according to claim 12, characterized in that the Raffkanten ( 6 ) of adjacent Roman wheels ( 1 ) in the axial direction of the guide pin ( 12 ) together a closed spiral revolution ( 13 ) form.

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