Tufting machine

Abstract

A tufting machine comprises push rods (1) spaced on the tufting machine and capable of reciprocating simultaneously. The needle bar is attached to the pushrod to move the needles on the needle bar through the backing media fed through the tufting machine. The first drive shaft (3) is rotatable in a first direction by a first motor (5) and is connected to a first set of the pushrods. The second drive shaft (4) is rotatable in the opposite direction by a second motor (8) and is connected to a second set of the pushrods. The first set of push rods alternate with the second set of push rods. A main drive shaft (54) is rotatable by a main drive motor (53) and coupled by a mechanical coupler to linearly reciprocate the needle bar. A rotary electric machine having a continuous one-way output is coupled to the eccentric crank arm to convert the continuous one-way output into a reciprocating rotary motion to rock the hook and / or knife drive shaft (51).

Description

[0001] The present invention relates to a tufting machine.

[0002] In particular, the present invention relates to a mechanism for reciprocating the needle bars of a tufting machine. The reciprocating speed of the needle bars determines the rate at which tufts can be formed in a backing material as it is fed through the tufting machine. To increase the productivity of the machine, this speed needs to be increased. However, the mechanism that drives the needle bars comprises a complex arrangement of rotating, pivoting, and linearly reciprocating components, resulting in a limitation in their reciprocating speed due to vibration and balance issues.

[0003] US4665845 discloses a single drive shaft connected to a plurality of push rods on a machine so as to reciprocate each push rod simultaneously, thereby reciprocating the needle bars.

[0004] This was improved in US5287819 which used a pair of drive shafts driven by a single motor and connected together by a timing belt. This was done to provide a dynamically balanced machine that could operate at higher speeds.

[0005] US Pat. No. 5,572,939 followed, criticizing US Pat. No. 5,287,819 for its use of a second drive shaft with associated supports and counterdrives at each end. The solution offered by US Pat. No. 5,572,939 was to omit the second drive shaft of US Pat. No. 5,287,819 and revert to the single drive shaft of US Pat. No. 4,665,845. In this case, the alternating drive assemblies for the alternating push rods were configured to rotate in opposite directions. The counter-rotation of the drive assemblies served to counteract a significant proportion of the horizontal rotational forces.

[0006] The present invention seeks to improve upon the prior art in order to provide a drive mechanism which can reciprocate the needle bar at a higher speed while maintaining vibration at an acceptable level.

[0007] According to a first aspect of the present invention, there is provided a tufting machine according to claim 1 .

[0008] Therefore, the present invention returns to the dual drive shaft of US 5287819. However, the problem mentioned in US 5572939 with respect to backdrive is solved by providing each drive shaft with its own drive motor.

[0009] In addition, the force required to drive the mechanism is now distributed across two motors, which provides more stable operation and produces less vibration. Current tufting machines can produce fabrics up to five meters wide. Because the components driving the platen mechanism and the motors driving the shaft itself are located at one or both ends of the shaft, current drive shafts can be relatively long (current tufting machines may have shafts exceeding seven meters), leading to more vibration problems.

[0010] When two drive shafts are used instead of one, each with its own motor, the push rods to be reciprocated are distributed over the two shafts and therefore over the two motors. A first set of push rods is connected to the first drive shaft to be driven by the first shaft rotating in a first direction, and a second set of push rods is connected to the second drive shaft to be driven by the second shaft rotating in a second direction opposite to the first direction.

[0011] Compared to a single axis with all loads and the motor on the same axis, the inertia of each axis is much lower. Lower inertia increases the natural frequency, making it possible to increase speed. When the first set of actuators alternates with the second set, a significant portion of the horizontal component of the rotational force is canceled out.

[0012] The first and second motors can be connected to the same ends of the first and second drive shafts. However, preferably, the first motor is connected to the first end of the first drive shaft, and the second motor is connected to the second end of the second drive shaft, which is opposite the first end of the first drive shaft. Thus, the two drive shafts are driven from opposite sides of the tufting machine, providing a balanced load. The significant separation of the motors provided by this arrangement further distributes the output force from the motors by preventing the push rods farthest from the motor from lagging behind push rods closer to the motor. Furthermore, position errors will be much smaller.

[0013] In order to optimize this effect, the two motors are preferably arranged so that the push rods are distributed symmetrically on the drive shaft.

[0014] Each respective drive shaft is connected to a respective drive motor at a power input point and to a respective push rod at a power output point spaced axially along the respective shaft, wherein the axial spacing between the power input point and the power output point is the same for both drive shafts. The connection between the drive motor and the drive shaft may not be a direct connection, but may be via an additional linkage, such as a belt, chain, or gears. The connection between the drive shaft and the push rod may not be a direct connection, but may be via an additional linkage, such as an eccentric coupling with a connecting rod and / or a belt, chain, or gears.

[0015] The first drive shaft and the second drive shaft can rotate mechanically completely independently of each other. In this case, the rotation of the motors should be carefully controlled to ensure that they rotate synchronously, so that the first set of push rods and the second set of push rods reciprocate simultaneously. Preferably, the first drive shaft and the second drive shaft are rotatably connected together. This ensures that the two drive shafts are synchronized. This also further helps to balance the load on the tufting machine. This should be contrasted with US5287819, in which the connection of the two drive shafts is necessary to transmit the driving force from a single motor from one shaft to the other. In contrast, in the present invention, the drive shafts are driven separately and are only connected to provide a simple way to ensure that the two shafts rotate synchronously.

[0016] The present invention also addresses the problem of how the table assembly is driven. In a cut-pile tufting machine, the table assembly includes a hook mechanism that swings back and forth to pick up a yarn loop as it is formed by a needle, and a knife mechanism that reciprocates relative to the hook to cut the yarn loop as it is formed on the hook. In loop pile tufting, a looper is provided instead of a hook and knife to pick up the yarn loop. This has a similar geometry to a hook used to produce cut pile, but does not have a cutting edge and is not provided with a knife. The term "hook" is used below and in the claims. It should be understood that this also covers loopers.

[0017] Typically, the hook and / or knife are driven by the main drive shaft (i.e., the drive shaft that reciprocates the needles). This can also be accomplished by a mechanical coupling comprising a push rod and cam arrangement. Alternatively, it can be accomplished using a belt drive, such as disclosed in US Pat. No. 5,513,586 and GB 2,307,701. Numerous coupling designs have been proposed to increase tufting speeds, and these are well summarized in the introduction to GB 2,307,701.

[0018] US 5979344 and US6827030 all disclose tufting machines, wherein, the mechanism for driving hook and knife is not coupled to the main drive shaft.In each case, linear actuator is provided to rock hook drive shaft and knife drive shaft.

[0019] The object of the present invention is to improve upon the prior art and to provide a drive mechanism for a table member capable of operating at a relatively high speed comparable to the relatively high speed of reciprocation of the needle according to the first aspect of the invention. However, it should be noted that the second aspect of the invention may be used independently of the first aspect if some other means of reciprocating the needle bar is used.

[0020] According to a second aspect of the present invention, a tufting machine according to claim 7 is provided.

[0021] Conventional practice is to couple the drives for the hook and / or the drive shaft to the main drive shaft, and instead this is now done with an auxiliary motor.

[0022] This offers a number of benefits. It significantly reduces the inertia of the tufting machine. This is the result of removing the coupling required to transmit the relatively high forces from the main drive (which is in the head of the tufting machine) to the drives for the hook drive shaft and / or knife drive shaft, which are located below the machine bed. In addition, it reduces the load required from a single motor, allowing the use of smaller motors and their distribution around the tufting machine.

[0023] Since the main drive shaft is no longer required to drive the table assembly, the needle movement is not affected by the operation of the table assembly. Although an additional motor is introduced, the use of a smaller motor and the elimination of a lengthy coupling require less space overall, allowing the tufting machine to be made more compact. Because the auxiliary motor can be closer to the hook drive shaft and / or the knife drive shaft and is dedicated only to driving these drive shafts, it can achieve higher speeds than the prior art. This arrangement also allows the timing of the hook drive shaft and / or the knife drive shaft to be controlled separately from the needle reciprocating motion, allowing greater flexibility in the phase difference between the two.

[0024] The use of a rotary motor with a continuous unidirectional output coupled to an eccentric crank arm provides advantages over US5979344 and US6827030. In particular, in these systems, the drive motor must be stopped each time the motion is reversed, which means periodic deceleration and acceleration, requiring more power. At the speeds at which the present invention is intended to operate, this is not an economical solution.

[0025] Furthermore, with a motor with a continuous unidirectional output coupled to an eccentric crank arm, the extreme positions of the mechanism are determined by the mechanism itself and are therefore independent of the control algorithms of the control electronics driving the motor. This allows for precise high-speed movement, as the movement is determined by the geometry of the mechanism and therefore does not change regardless of the speed used.

[0026] To adjust the drive motion, the crank arm can be replaced with a crank arm of different length and / or an eccentric coupling designed to give the desired motion profile. This is a simple change to make and ensures that accuracy is maintained at high speeds for a variety of motion profiles.

[0027] In a cut-pile tufting machine, an auxiliary motor can drive both the hook drive shaft and the knife drive shaft by mechanically coupling the auxiliary motor to the two shafts. This provides a simpler drive. Alternatively, the auxiliary motor drives the hook drive shaft, and another motor drives the knife drive shaft. This is a more complex mechanism, but allows the hook timing to be varied independently of the knife timing.

[0028] There may be a single auxiliary motor. However, preferably, there are two auxiliary motors, one at each end of the hook drive shaft and / or knife drive shaft. This reduces the load on the individual motors, thereby providing better load distribution and a more balanced drive.

[0029] An example of a tufting machine according to the present invention will now be described with reference to the accompanying drawings, in which:

[0030] Figure 1 is a perspective view showing the top portion of the needle bar drive mechanism in the head of the machine according to the first aspect of the present invention;

[0031] Figure 1A It is a three-dimensional part of the drive, showing the connection of the shaft;

[0032] Figure 2 is a front view of a portion of a needle bar drive mechanism that drives two push rods;

[0033] Figure 3 is a perspective view showing the operating principle;

[0034] Figure 4 is a schematic plan view illustrating the operating principle;

[0035] Figure 5A yes Figure 3 an end view of a first end of

[0036] Figure 5B yes Figure 3 end views of opposite ends of;

[0037] Figure 6 is a perspective view of a lower portion of a drive mechanism according to the first aspect of the present invention; and

[0038] Figure 7 Shown Figure 6 The first motor configuration.

[0039] Most parts of the tufting machine are conventional and are shown for example in US4665845, US5287819 or US5572939.

[0040] A first aspect of the invention relates to improvements in the drive mechanism for the needle bars. A second aspect of the invention relates to improvements relating to the drive mechanism for the hooks (or loopers) and, optionally, also to improvements relating to the drive mechanism for the knives as described below. In the following description, only the term "hook" is used, and it should be understood that this also covers the loopers. All other features of the tufting machine are conventional and well known in the art.

[0041] Figure 1 The drive mechanism for the needle bar is shown.

[0042] like Figure 1 As shown, there are ten push rods 1 extending vertically downward from a drive mechanism 2. The push rods 1 are connected to needle bars (not shown) at their lower ends in a conventional manner. The push rods 1 are driven synchronously so that the needle bars are driven to reciprocate in a vertical plane, thereby driving the needles in and out of the backing material fed laterally through the tufting machine to produce a tufted carpet.

[0043] The present invention relates to a driving mechanism for causing a push rod 1 to reciprocate. Figures 1 to 5B The drive mechanism is described in more detail. The drive mechanism is provided by a first drive shaft 3 and a second drive shaft 4, which extend parallel to each other across the entire width of the tufting machine. The first drive shaft 3 is driven by a first motor 5 via a pair of pulleys 6 (only one of which is Figure 1 The other is seen behind the first motor 5) and driven by belt 7. The second drive shaft 4 is similarly driven by the second motor 8 via a similar pair of pulleys 9 and belt 10.

[0044] Each drive shaft 3, 4 is rotatably supported by bearings (not shown) and a drive assembly 12 along the length of both shafts.

[0045] The synchronization of the shafts 3, 4 can be controlled by the tufting machine controller and / or the motor controller. Additionally or alternatively, a corresponding pair of bevel gears 13 can be provided at each opposite end of the shafts 3, 4, which mesh with each other to ensure that the two shafts 3, 4 rotate together. Figure 1A Shown in more detail in .

[0046] The drive shafts 3 and 4 are connected to the push rod 1 in the following manner: Figure 4 The drive assembly is divided into two sets, namely the first set 12A connected to the first drive shaft 3 and the second set 12B connected to the second drive shaft 4. For simplicity, Figure 1 Five examples of each type of drive assembly are shown. Figure 3 One of each group is shown schematically, and Figure 4 Schematically shown are two groups comprising a drive assembly 12A connected to the first drive shaft 3 and a drive assembly 12B connected to the second drive shaft 4. Figure 4 In , rectangles indicate groups as shown on the right and left, and there are symbolic representations of more groups in between.

[0047] The first and second drive assemblies 12A, 12B alternate across the width of the machine and are connected alternately to the first and second drive shafts 3, 4 by means of first and second belts 15, 16 respectively. Figure 2 and Figure 3 Such a set of drive assemblies 12A and 12B are shown in front view and perspective view, respectively.

[0048] The drive assemblies 12A, 12B are substantially identical in most respects, and common features will be described below.

[0049] The first drive arrangement comprising the first motor 5 and the first drive shaft 3 is essentially rotationally symmetrical to the second drive arrangement comprising the second motor 8 and the second drive shaft 4, in that if one of the drive arrangements is rotated about the central vertical axis, it will be directly mapped onto the other drive arrangement in terms of the axial position of the power input and output of each drive shaft 3, 4.

[0050] In other words, if the respective drive shaft 3, 4 is connected to the respective drive motor 5, 6 at a power input point and to the respective push rod 1 at a power output point axially spaced along the respective shaft, the axial spacing between the power input point and the power output point is the same for both drive shafts 3, 4. In addition, preferably, the distance between each motor 5, 8 and its respective shaft 3, 4 is also the same for each drive device, so that the same length of belt 7, 10 is used in each case.

[0051] The only difference between the first drive assembly 12A and the second drive assembly 12B is that for the first drive assembly 12A, the belt 15 is driven by the first drive shaft 3 , while for the second drive assembly 12B, the belt 16 is driven by the second drive shaft 4 .

[0052] The belts 15, 16 are connected to a top pulley which, for each drive assembly 12A, 12B, is rotatable with a stub shaft 29 which is eccentrically coupled to a connecting rod 35 which reciprocates the push rod 1 vertically in a manner well known in the art.

[0053] Therefore, the shafts 29 for the first drive assembly 12A and the second drive assembly 12B will rotate in opposite directions. The axes of the stub shafts 29 are all located on the same line (see Figure 1 and Figure 2 ). Due to the helical gear 13 (or some other timing mechanism provided by the motor controller or tufting machine controller), shafts 3 and 4 rotate synchronously so that shaft 29 will rotate at the same speed in the first drive assembly 12A and the second drive assembly 12B. The eccentric coupling between shaft 29 and connecting rod 35 has the same equivalent geometry for the first drive assembly 12A and the second drive assembly 12B, and the two eccentric couplings are in phase with each other. This geometry is symmetrical about the mid-plane so that the path of travel of connecting rod 35 is the same for the first drive assembly 12A and the second drive assembly 12B. The components of the drive units rotate in opposite phase to ensure that their vertical motion components are exactly the same. In this way, the first set of push rods and the second set of push rods reciprocate simultaneously.

[0054] Although the above arrangement provides a well-balanced mechanism, some counterweight may still be required to dampen any vibrations that naturally occur. This can take the form of an eccentric counterweight mounted on the eccentric drive shaft 29 and / or a conventional eccentric mass that rotates with the first drive shaft 3 and / or the second drive shaft 4.

[0055] Now refer to Figures 6 and 7 A second aspect of the present invention is described.

[0056] Figure 6 A drive mechanism 50 for the table top assembly is shown. This will be mounted in the tufting machine in use, below the table top. In conventional tufting machines, this will be connected by a mechanical linkage to be driven by the main drive assembly as described above.

[0057] Figure 6 The mechanism 50 shown is for driving a hook shaft 51. However, the same principles apply to the drive for the knife shaft.

[0058] The hook shafts rock back and forth (as described below) to move the hooks back and forth relative to their respective needles, which reciprocate up and down to pick up the needle's yarn loops.

[0059] The drive mechanism for the hook shaft 51 will now be described.

[0060] This takes the form of a pair of motors 53, positioned one adjacent each end of the hook shaft 51. The motors have continuously rotating output shafts 54, which are coupled to the hook shaft 51 via eccentric couplings 55. This includes a connecting rod 56, which is rotatably and eccentrically mounted at its top end to the output shaft 54. The bottom end of the connecting rod 56 is rotatably mounted to a bracket 57 attached to the hook shaft 51.

[0061] The rotation of the output shaft 54 causes the top end of the connecting rod 56 to perform an orbital motion about the axis of the output shaft 54. In its upward stroke, the connecting rod 56 lifts the bracket 57, and in its downward stroke, the connecting rod 56 lowers the bracket 57, thereby causing a rocking motion of the bracket 57 and, therefore, a rocking motion of the hook shaft 51.

[0062] The eccentric coupling is configured to provide the aforementioned rocking mechanism. The motor 53 effectively provides the rotational force previously provided by a mechanical coupling to the main drive shaft in the prior art. The motor is mounted at the point where the coupling to the main drive shaft is mounted in the prior art, allowing it to utilize any known coupling to the hook shaft 51. Consequently, the drive mechanism is significantly simpler and smaller than a coupling to the main shaft.

[0063] In a tufting machine, there can be a dedicated set of motors for the hook shaft and the cutter shaft, or both can be coupled to the same set of motors. A single motor can be set on one side of the tufting machine. However, using a pair of motors provides a more balanced and better distributed drive.

[0064] The motor 53 is mounted directly to the eccentric coupling, as Figure 7 As an alternative, a belt can be provided to allow coupling to an offset motor. This provides the option of moving the motor to a different position if this is more convenient for the layout of a particular machine.

Claims

1. A tufting machine, comprising: a plurality of push rods spaced apart on the tufting machine and capable of simultaneous reciprocating motion; a needle bar attached to the pusher so as to be reciprocated by the pusher to move, in use, needles on the needle bar through a backing medium fed through the tufting machine; a first drive shaft rotatable in a first direction by a first motor, the first drive shaft being connected to a first set of push rods in the push rods to enable the first set of push rods to reciprocate; and a second drive shaft rotatable in a second direction opposite to the first direction by a second motor, the second drive shaft being connected to a second set of push rods in the push rods to reciprocate the second set of push rods; Wherein, the first set of push rods and the second set of push rods alternate.

2. The tufting machine according to claim 1, wherein: The first drive shaft and the second drive shaft are rotatably connected together.

3. The tufting machine according to claim 1 or 2, wherein: The first motor is connected to a first end of the first drive shaft, and the second motor is connected to a second end of a second drive shaft, the second end of the second drive shaft being opposite the first end of the first drive shaft.

4. The tufting machine according to claim 3, wherein: Each respective drive shaft is connected to a respective drive motor at a power input point and to a respective push rod at a power output point spaced axially along the respective shaft, and The axial distance between the power input point and the power output point is the same for the two drive shafts.

5. Tufting machine according to any one of the preceding claims, further comprising an auxiliary motor coupled to the swing hook drive shaft and / or the knife drive shaft.

6. The tufting machine according to claim 5, wherein: The auxiliary motor is a rotary motor having a continuous unidirectional output, and the rotary motor is coupled to an eccentric crank arm to convert the continuous unidirectional output into a reciprocating rotary motion, thereby swinging the hook drive shaft and / or the knife drive shaft.

7. A tufting machine, comprising: a main drive shaft rotatable by a main drive motor and coupled by a mechanical coupling to cause linear reciprocating motion of the needle bar, thereby, in use, moving needles on the needle bar through a backing medium fed through the tufting machine; and A rotary motor having a continuous unidirectional output is coupled to the eccentric crank arm to convert the continuous unidirectional output into a reciprocating rotary motion to rock the hook drive shaft and / or the knife drive shaft.

8. Tufting machine according to claim 7, comprising two auxiliary motors, one at each end of the hook drive shaft and / or knife drive shaft.

9. The tufting machine according to claim 7 or 8, wherein: The crank arm is driven by the auxiliary motor via a belt.

10. Tufting machine according to any one of claims 7 to 9, wherein The auxiliary motor drives both the hook drive shaft and the knife drive shaft.

11. The tufting machine according to any one of claims 7 to 9, wherein The auxiliary motor drives the hook drive shaft, and at least one additional motor drives the knife drive shaft.

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