Needling machine with sliding rod

Details Needling machine with sliding rod Needling machine with sliding rod

1997-07-06

1998-10-20

Nerbun, Peter

Textiles: manufacturing

Textile product fabrication or treatment

Fiber entangling and interlocking

28107, D04H 1800

Patent

active

058228349

DESCRIPTION:

BRIEF SUMMARY
BACKGROUND OF THE INVENTION

The present invention relates to a needling machine used for the mechanical consolidation of a sheet--or fleece--of fibres coming, for example, from a spreading and fleecing machine (so-called "cross-lapper").
Known needling machines comprise a support called a board on which needles are fixed. By means of crank and connecting rod devices, the board is reciprocated in order that these needles traverse the sheet of fibres at a production rate which can be of the order of 1000 to 2000 strikes per minute.
The alternating--i.e. reciprocating--motion of the needle board is obtained by means of a crank and connecting rod device.
Complementary devices also make it possible to regulate the flow of fibres entering and leaving the machine, with or without stretch, and at speeds chosen according to the strike rate expressed as a number of strikes per minute, which is equivalent to the number of alternating movements of the needles per minute.
The major disadvantage of these needling machines is in their speed limitation, which is incompatible with increasing production rates. In fact, the market requires increasingly fast machines.
Conventionally, the connecting rod of each crank and connecting rod device extends between an eccentric, connected to a motor, and an articulation at the end of a sliding rod to which is fixed a needle board support. In order that it may slide, the sliding rod passes through two slide bearings located at a certain distance from one another.
This arrangement has many disadvantages. When the board is at the end of its travel at which the needles are withdrawn from the product, the articulation of the rod is distant from the bearings and consequently the connecting rod applies forces to the sliding rod under poor guidance conditions, creating large flexion moments in the sliding rod and high stresses in the bearings. In order to lighten the system and reduce its overall height, there is a temptation to reduce the length of the connecting rod. But this increases the angular stroke of the connecting rod about the articulation with the sliding rod and therefore increases the value of the undesirable transverse force component which is transmitted to the rod's slide bearings. It is the bearing closest to the articulation which is particularly dangerously loaded, typically by three to ten times as much as the other one. These bearings are subject to their maximum load, with a jamming tendency which becomes greater as the inclination of the connecting rod becomes greater, when the connecting rod pushes the sliding rod in order to make the needles penetrate into the fibrous products. Instead of shortening the connecting rod, it is possible to consider shortening the sliding rod. But this would result in bringing the two slide bearings towards each other in an exaggerated manner to the point at which the sliding rod would no longer be guided with sufficient accuracy. Thus, up to the present time, bulky assemblies have been tolerated in which the mobile systems are heavy and consequently produce lots of vibration whilst obliging manufacturers to limit the operating speed.
GB-A-1 343 763 indeed proposes an arrangement in which the articulation between connecting rod and sliding rod is placed inside the sliding rod which is made in tubular form. Thus the slide bearing at the crank end can be placed closer to the crank because the articulation can, at least for certain angular positions of the crank, be engaged in the slide bearing. But the bearings then have a very large diameter and in practice it proves that their fluid-tightness is then difficult to achieve. The sliding rod is heavy and the assembly is expensive. U.S. Pat. No. 3,798,717 and FR-A-2 224 579 overcome this difficulty by placing the articulation such that it is always located between the upper and lower slide bearings but the assembly then becomes very complex mechanically and expensive.
The purpose of the present invention is thus to propose a simple needling machine which can function continuously at high sp

REFERENCES:
patent: 3798747 (1974-03-01), Brochetti
patent: 3889326 (1975-06-01), Tyas
patent: 4891870 (1990-01-01), Muller
patent: 4977653 (1990-12-01), Pum

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