Sewing – Special machines – Embroidering
Reexamination Certificate
2000-07-10
2001-07-24
Izaguirre, Ismael (Department: 3765)
Sewing
Special machines
Embroidering
C112S080730
Reexamination Certificate
active
06263811
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a tufting machine for tufting a background pile and inserting or overtufting additional pile at predetermined locations to form a pattern in the background pile.
In the tufted carpet industry, there is a demand for machines which are able to produce a carpet of one or more background colors with an intermittent pattern of one or more pattern colors. Such a carpet is conventionally produced in one of two different ways.
The most common process is to bury the color used for the pattern in the parts of the carpet where the pattern is not required. This is done by tufting with the pattern color at the lowest possible pile height in the areas between the pattern. This is reasonably satisfactory for carpets with a high pile height. However, even then, it is difficult to control the yarn feed to produce a single tuft of the pattern, and it is also wasteful of yarn to tuft at a low pile height in areas that will not be seen. However, the real problem with this method is for carpets with a low pile height, for which there is an increasing demand in certain markets, where it becomes impossible to hide the buried color. This technique is therefore not suitable for producing such patterned carpets at low pile heights.
A second technique is known as overtufting. This is simply where the carpet is tufted by a first tufting machine with the background color, and is then fed through a second tufting machine where the pattern is tufted into the carpet, the second machine being a controlled needle individual controlled needle machine. Examples of this process are illustrated in U.S. Pat. Nos. 4,693,190 and 4,726,306. With this method precise control of the positioning of the pattern is impossible preventing a tuft of the pattern from being placed precisely between tufts of the background color. Not only can this affect the aesthetics, but it can also cause tufts of the background color to be punched out, pierced or split as the pattern is created making this method generally unsuitable for loop pile carpets. Additionally, the machines which produce these fabrics are controlled needle cut pile machines, loop pile machines of such type not being known. Also, as passes through two tufting machines are required, this process is slow.
SUMMARY OF THE INVENTION
According to the present invention, provides a tufting machine having first and second needle bars which are reciprocably operable within the housing and on each of which a plurality of needles are mounted for reciprocating toward and away from a web of backing material fed through the machine, the first and second needle bars being spaced in the direction in which the web travels through the machine, and a control mechanism which controls the reciprocation of the needles on one needle bar independently of those on the other needle bar.
By providing two needle bars with independent control, one can be used to tuft the background, while the other can be used to tuft the pattern. Because the two sets of needles are independently controllable, the one set of needles which is tufting the pattern can be stopped from tufting when the pattern is not required. Thus, rather than tufting the pattern with a low pile height, the yarn for the pattern can simply be left to trail along the back of the carpet when it is not being used to create the pattern. Not only does this use less yarn than is required to tuft with a low pile height, but most importantly, it is impossible to see even when the background is tufted with a very low pile height.
Further, the independent control of the two needle bars allows a pattern requiring only a single tuft of the pattern at any one point to be tufted, thereby producing a well defined pattern.
The two needle bars may be very easily positioned with respect to one another. This means that the loopers which produce the background can be precisely aligned with respect to the loopers which produce the pattern such that very precise positioning of the pattern with respect to the background can be achieved. For example, the machine of the present invention can produce a carpet in which the pattern is precisely located between rows of the background. This avoids the problems associated with overtufting in which background tufts can be punched out and where it is not possible to control the position of the needles which produce the background with respect to the needles which produce the pattern. The invention can therefore be used for both cut and loop pile tufting machines.
The first and second needle bars may each be provided with their own entirely independent reciprocating mechanism. However, to reduce the complexity of the machine, and to provide better control of the synchronization of the two needle bars, the preferred mode of the invention is for the two bars to share a common drive mechanism, and for the needles of at least one of the bars to be retractable independently of the needles on the other needle bar. In practice, to produce a carpet with a background and a pattern, it is only necessary to have retractable needles on the needle bar used to produce the pattern. In this way, the drive mechanism will reciprocate both needle bars. When the needles on the needle bar tufting the pattern are retracted, only the background color will be tufted. At this time, the yarn to these needles trails along the back of the backing medium. A yarn feed mechanism may then control the feed of yarn so that this yarn is tight to the back of the carpet. On each occasion when a tuft of pattern is required, the needles on the bar forming the pattern are moved to their extended position, whereupon they begin tufting together with the needles producing the background. The needles can be extended only for long enough to create a single tuft if necessary.
The needles may be retractable using any suitable mechanism such as a mechanical, electromagnetic or hydraulic mechanism, but the current preference is for a pneumatically operated retraction mechanism.
In order to allow more complex patterns to be produced, it is preferable for at least one of the needle bars to be moveable transversely to the direction in which the backing material is fed through the machine. If the needles forming the pattern are laterally moveable in this way, then they can be controlled to move across the web between pattern tufts, thereby allowing an offset or checkerboard pattern to be produced.
The present invention is applicable to a tufting machine in which the needles are mounted via needle modules, and a plurality of such needle modules are mounted to each needle bar. In this case, on at least one of the needle bars, the reciprocation of each module can be independently controlled to allow more complex patterns to be produced. As an extension of this, it is envisaged that on at least one of the bars the reciprocation of each needle may be independently controllable, as in the known individual controlled needle machines one of which is illustrated in U.S. Pat. No. 5,653,184, to provide an even greater degree of flexibility.
REFERENCES:
patent: 4815402 (1989-03-01), Price
patent: 4831948 (1989-05-01), Itoh et al.
patent: 4852505 (1989-08-01), Dedmon
patent: 5143003 (1992-09-01), Dedmon
patent: 5383415 (1995-01-01), Padgett, III
patent: 5706744 (1998-01-01), Card et al.
patent: 6202580 (2001-03-01), Samillo
patent: 2246371 (1992-07-01), None
Izaguirre Ismael
Ruderman Alan
Spencer Wright Industries, Inc.
Stark Stephen J.
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