GB2026046A - Improved rotary braiding machine - Google Patents

Abstract

A rotary braiding machine, particularly for forming a braid or shielding cover on coaxial cables comprises a plurality of filament stock feeding fingers (17) movable in synchronization with the rotary movement of spool carrying first and second upper and lower platforms (8, 10) and effective to feed the filament stock of the lower spool carrying platform (10) in such a way as to avoid the filament stock from the upper spool carrying platform (8) thereby forming the braid. The drive is controlled by a variable pulley arrangement to vary the braid produced. A body 34 moving to and fro on a screw a carries rods 37, 38 which engage the covered cable 4 to distribute it evenly on the reel. <IMAGE>

Description

SPECIFICATION Improved rotary braiding machine This invention relates to an improved rotary braiding machine.

As is known, a braiding machine is an apparatus used for wrapping electric conductors, coaxial cables, tubes and the like with a yarn or wire braid of various materials, e.g. of copper. Such braiding machines comprise a plurality of yarn, or wire, carrying spindles which are arranged to spin on a generally stationary platform, half of them in a righthand and half in a left-hand direction, such as to result in the formation of the braid, the yarns or wires which are connected to the central cable to be wrapped being fed from a suitable reel.

Conventional braiding machines are not entirely devoid of shortcomings, among which low spindle speed capabilities and, consequently, a low braiding rate or braid formation speed, the inability to change the spindle speeds of rotation, eccessive noise, thereby the machine operators are compelled to wear ear protection caps, considerable bulk, as well as an often quite high cost. In addition thereto, the conventional braiding machines only permit the braid pitch to be varied within an extremely narrow range of values, which reflects in a poor flexibility or adaptability of the machine, which cannot meet the user's more specific requirements, and in particular cannot accommodate a range of braiding patterns.Moreover, the operative intervals of such known braiding machines are quite limited, and frequent stops are required for an operator to replace the exhausted spindles, which increases the operating costs, and accordingly the unit cost of the resulting product. Lastly, a common problem to such known braiding machines is that the yarn or wire is generally allowed to slip, thereby certain types of braids, such as tin plated wire braids, cannot be produced on them.

In view of the aforementioned and other disadvantages of conventional braiding machines, and more specifically of rotary braiding machines intended for forming a shielding braid on coaxial cables, this invention sets out to provide a novel and improved rotary braiding machine, particularly for forming a wire braid over a coaxial cable, which is capable of operating at high speeds, such as to develop a high production rate, as expressed in terms of linear meters of braided cable per hour.

Within that general aim, it is possible to arrange that the braiding machine of this invention comprises means for varying in an almost continuous manner and within a wide range the braid pitch, such as to produce braids having any desired pattern.

It is further possible to arrange for the braiding machine of this invention to have long operating duration capabilities, and thus capable of covering with the braid a longer length of coaxial cable, while only requiring a minimal intervention by an operator for load ing the machine with the material for forming the braid or braided cover.

It is also possible to arrange that the braid ing machine of this invention comprises means effective to ensure optimal unwinding of the coaxial cable to be covered from a feed thereof, and an as optimal winding of the braid covered coaxial cable onto a pick up member for said covered coaxial cable.

It is further possible to arrange that the braiding machine of this invention, particularly for forming a shielding braid cover on coaxial cables, operates in an extremely silent or noiseless manner.

Also possible is to arrange for the braiding machine of this invention to produce differently patterned braids, either with wires (in particular tin plated ones), or textile yarns, or glass fibers, the switch from one type of filsment stock to another being performed without readjusting the filament stock tensioning springs.

According to one aspect of the present invention, there is provided an improved rotary braiding machine, particularly for forming a braid or shielding cover on coaxial cables, comprising: (a) a stationary frame; (b) a first reel for feeding the cable stock to be covered with said braid, said first feed reel being carried rotatively at one side of said stationary frame; (c) a second pick up reel for picking up the covered cable, adapted for receiving and storing said braid covered cable, said second reel being carried rotatably at an opposite side of said stationary frame; (d) a first platform carrying a first plurality of filament stock carrying spools, said first spool plurality being mounted for idle rotation, and said first platform being adapted for rotating in a substantially horizontal plane such as to drive said first spool plurality to rotate;; (e) a second platform coaxial with said first platform and carrying a second plurality of filament stock carrying spools, said second spool plurality being mounted for idle rotation, and said second platform being adapted for rotating in a substantially horizontal plane above said first platform and in the opposite direction thereto, such as to drive said second spool plurality to rotate, said filament stock carrying spools of said first and second platforms cooperating function-wise together to form said braid on said coaxial cable; (f) motor and guiding means function-wise arranged between said first and second reel and adapted for picking up said cable stock to be covered from said first reel and guiding said covered cable on said second reel;; characterized in that it comprises filament stock feeding means movable with swinging reciprocating motion in synchronization with the rotary movement of said first and second reels and of said first and second platforms, said filament stock feeding means being effective to feed said filament stock of said lower spools while avoiding the filament stock from the upper spool thereby forming said braid.

Further features and advantages of the braiding machine according to the invention will be more clearly understood from the following detailed description of a presently preferred embodiment thereof, illustrated by way of example and not of limitation in the accompanying drawings, where: Figure 1 is a perspective view of the braiding machine according to this invention in its entirety; Figure 2 is a detail view showing the spool assembly of the braiding machine of this invention; Figure 3 is a schematical view showing the arrangement of component parts for actuating the spool assembly of the braiding machine according to this invention; Figure 4 illustrates the assembly comprising the hollow cam controlling the entrainment catches associated with the braiding machine of this invention;; Figure 5 is a schematical view of a speed variator unit associated with the braiding machine of this invention; Figure 6 is a plan view of the unit of Fig. 6; Figure 7 and 8 illustrate schematically a cable distributing or unwinding unit associated with the braiding machine according to the teachings of this invention; and Figures 9A and 9B show the actuating mechanism for the yarn, or wire, feeding fingers of the lower spools.

With reference to the drawing figures, and in particular to Fig. 1, there is shown a perspective general view of the braiding machine according to the teachings of this invention. The braiding machine is indicated generally at 1. It will be observed that the braiding machine 1 comprises a stationary frame 2, whereon is mounted a first reel 3 or reel for feeding the cable stock 4 to be covered with the braid, the reel 3 being carried rotatably at the front (or side facing the machine operator) of the frame 2. At the opposite side, the frame 2 carries a second reel 5 or covered cable pick up reel adapted for taking up and storing said cable once it has been covered with said braid, the braiding area being indicated at 7.On the frame is also supported a first platform 8 carrying a plurality of spools 9 loaded with a yarn or wire, e.g. of copper, and supported for idle rotation, said first platform 8 being adapted for rotating in a substantially horizontal plane, such as to drive rotatively said first plurality of spools 9. The frame 2 also carries a second platform 10, coaxial with said first platform 8, which provides support for a second plurality of filament stock (e.g. copper wire) carrying spools 11, also supported on the platform 10 for idle rotation, said second platform 10 being adapted for rotating in a subsantially horizontal plane below said first platform 8, in the opposite direction to the platform 8 itself, for driving said second plurality of spools 11 to rotate.The spools 9 and spools 11, while in operation, cooperate function-wise together to form the braid or braided cover, at the area 7, on said coaxial cable 4. It should be noted that in the preferred embodiment just described, the upper spools 9 and lower spools 11 are eight in number, although the Applicant has already carried out exhaustive studies for developing specific constructions also for platforms which include a higher number of spools and specifically twentyfour and thirtytwo spools. In particular, the upper platform 8 and lower platform 10 receives their movements from the machine main drive, as will be explained hereinafter, and rotate, as mentioned, in opposite directions at substantially the same speed.

It should be further added to the above description that the frame 2 also supports a guide wheel 1 2 which is located for operation between the first reel 3 and second reel 5, the guide wheel 1 2 also receiving its motion from the machine drive and being adapted for picking up the cable stock 4 to be covered from the first reel 3 and guiding the covered cable, emerging from the area 7, to the second reel 5. On the frame 2 of the braiding machine, at the pick up reel 5 and above it, there is positioned also an unwinding unit or movable distributor, not shown in Fig. 1, but visible in Figs. 7 and 8. This unwinding unit will be described in detail hereinafter. It will be enough to say now that the unwinding unit extends across the frame 2 of the machine along the width direction thereof.

Lastly, and advantageously, the frame 2 includes a speed variator unit, generally indicated at 13.

With more specific reference to Fig. 2, there are illustrated therein the two sets of spools 9 and 11, supported respectively on the upper platform 8 and lower platform 10.

These spool sets, along with their rotary piatforms, were the subject of Italian Patent No.

1.004.124, issued on July 10, 1 979 to this Applicant. Thus, reference should be made to that Patent for a detailed description of the two sets of spools and of their cooperative operation in forming the braid, this specification being limited to pointing out the differences from the cited Patent, more detailed emphasis being placed on the novel aspects of the braiding machine according to this invention.

More specifically, the lower spools 11 have an inclined position or attitude, advantage ously a 45 one, on the rotation plane and are attached to carriages 14 arranged to run in circular runways 1 5. The filament stock 16, either a wire or yarn one, from each spool 11 is passed through a feeding finger 1 7 and is connected to the central cable 4 to be covered. It will be noted, that also the filament stock from the upper spools 9 is connected to the cable 4 to be covered, the spools 9 being also carried on plate elements 1 8 which are movable along circular guides. Contrary to the braiding machine disclosed in the cited Patent to the same Applicant, the spools 9 are individual ones, whereas in the prior Patent braiding machine the spools 9 were combined in pairs.By splitting the spools 9 in single elements, an extremely high braiding rate or speed has been achieved, as well as the possibility of producing braids with a 1 to 1 braiding ratio and any desired pattern.

Furthermore, and with reference also to Fig.

4, there can be observed specifically the upper hollow cam 1 8 having sixteen rises and sixteen descents for controlling the upper spools 9, and the lower cams, respectively 1 9 and 20, having four rises and four descents, for controlling the lower spools 11. The cam 20 is constantly abutting against a bearing or pivot member 21 which controls, through a shaft 21', a set 22 for the reciprocating movement of the cited feeding fingers 1 7.

The movement of each individual feeding finger 1 7 being synchronized, by virtue of the cited cams 18, 1 9 and 20, with the rotation of the upper and lower platforms.

It is considered that the above description is also sufficiently extensive to make clear the braiding process operation as well, which characterizes the instant machine. For a more detailed description, reference can be made to the cited Italian Patent to the same Applicant.

More specifically, the cited sets 22 are operative to drive the feeding fingers with a back and forth reciprocating motion in synchronization to avoid the yarns, or wires, from the upper spools 9. To this aim, essential are the catches or tooth-like members 24, which are provided two in number for each upper spindle 9, the up and down reciprocation whereof is indicated by the arrow and is controlled by the hollow cam 1 8 in engagement with the roller 25. Since the platforms rotate in opposite directions, the yarns, or wires, from the lower spools are diverted,with a pendulum-like movement, by means of the feeding fingers 1 7 which direct them alternately above and below the spool carrying carriages, such as to form the braid intended for covering the central cable 4.As mentioned, the spool sets, and their platforms, and related actuating members are substantially similar to those described in the cited Patent No. 1,004,124 to this Applicant, the invention's improvement residing in that the upper spools 9 are single or individual ones and not pairs like in the prior Patent, and in that novel members are provided for actuating the feeding fingers 1 7 (Fig. 10). This afforded, as mentioned, a considerable increase of the braiding rate. A specific feature of the braiding machine according to this invention, is instead the speed variator unit indicated generally at 1 3 in Fig.

1. In the conventional braiding machines, to carry out the braiding with different cable pitches, one was obliged, heretofore, to replace the gears, which is a time-consuming procedure that cannot provide variation within a very wide range, since as will be appreciated, the braiding pitch depends on the particular gears employed.

According to the invention, by contrast, the braiding machine 1 is equipped with a continuous type of variator unit, as shown in detail in Fig. 5. It will be appreciated how the variator unit 1 3 comprises basically two pulleys 26 and 27, between which pulleys a reinforced cogged belt 28 is stretched. The unit 1 3 is associated with the upper portion of the frame 2, derives its motion from the machine main drive, and controls the rotational speed of the wheel 12, the variation whereof will cause the braiding pitch to vary.

Specifically, the braiding pitch change will be effected by actuating the handwheel 29 of the unit 1 3. In fact, by rotating the handwheel 29 in a suitable direction, the belt 28 can be displaced transversally to a greater or smaller extent, the pulleys 26 and 27 being of the adjustable element type. By displacing the pulley 28, one accomplishes, as is apparent, a variation in the drive ration between the two pulleys 26 and 27, and accordingly a variation in the speed of the wheel 1 2. An essential element in this speed variator unit is the biasing spring 30, associated with the pulley 27.

Making now reference specifically to Figs.

7 and 8, there is illustrated a further characterizing unit associated with the braiding machine of this invention, such a unit being termed "distributor" or "unwinding" unit and indicated generally at 31. The unit 31 has the function of evenly distributing the braid covered cable 4 over the full width of the pick up reel 5. To this aim, and with reference to the Figs. 7 and 8, the frame 2 carries, arranged transversally thereto, a fixed screw 32 and a movable rod-like element 33, driven of rotary motion, wherebetween is arranged the body 34 of the instant distributor or unwinding unit. On the screw 32, there are arranged two stop elements, respectively a right and left one, 36 and 35, which are adjusted in accordance with the width of the pick up reel. The body 34 engages through two pivotable rods 37,38 the braid covered coaxial cable 4 to distribute it evenly across the width of the pick up reel, because the body 34 reciprocates itself rectilinearly to right and left, to automatically reverse its movement as a result of its alternate engagement with the stopping members 35 and 36, respectively.

With reference to Figs. 9A and 9B, this novel and improved unit for actuating the feeding finger 17 comprises a gear ring 39 which replaces the cams 1 9 and 20 of Fig. 4, an idle coupled gear 40 rotating oppositely to the gear 39 and replacing the roller 21 (Fig.

4), a pin 41 driven rotatively by 40 and replacing the pin 21', and a further gear 42 which, together with the members 43 and 44, totally replaces the unit 22 of Fig. 4. The movement is imparted to the feeding finger 1 7 by a camming drum having a continuous groove, thereby that movement is attenuated and subjected to no sharp reversals. This solution, proposed as an alternative to the former, affords a considerable reduction of the machine costs, both operating and maintenance.

It will be apparent from the foregoing that the invention fully achieves its objects. In particular, a braiding machine has been provided which is extremely compact and includes novel and improved means adapted to ensure, on one side, a high braiding rate, and on the other side, almost infinite variability of the braiding pitch, as well as an optimal winding and distributing of the braid covered cable onto the pick up reel. Thanks to such technical innovations, and specifically thanks to the speed variator unit, the cable distributor or unwinding unit, and the feeding finger control unit, the braiding machine of this invention constitutes a modular apparatus of high affectiveness, which only requires minimal attention by its operators.

While the invention has been described with reference to a specific, presently preferred, embodiment thereof, it should be noted that it is susceptible to several modifications and variations thereof, which are all intended to fall within the scope of the instant invention. In particular, while in the above description specific reference has been made to a braiding machine having eight upper spindles and eight lower spindles, the machine may include any number of spindles, and more specifically, the Applicant has already studied and designed a braiding machine with 24 and 32 spindles respectively, wherein the braiding rate achieves extremely high levels, thus affording a high output, as expressed in terms of linear meters of cable covered with braid per hour. In addition thereto, it is also possible to vary the spindle arrangement, and more specifically the upper yarn or wire spindle arrangement, again for the purpose of optimizing the cable covering rate. In particular, the Applicant has already completed successful tests, wherein the upper spindles have been arranged almost horizontally, and a still higher braiding rate has been achieved.

Claims (11)

1. An improved rotary braiding machine, particularly for forming a braid or shielding cover on coaxial cables, comprising: (a) a stationary frame; (b) a first feed reel for feeding the cable stock to be covered with said braid, said first feed reel being carried rotatively at one side of said stationary frame; (c) a second pick up reel for picking up the covered cable, adapted for receiving and storing said braid covered cable, said second reel being carried rotatably at an opposite side of said stationary frame; (d) a first platform carrying a first plurality of lower filament stock carrying spools, said first spool plurality being mounted for idle rotation, and said first platform being adapted for rotating in a substantially horizontal plane such as to drive said first spool plurality to rotate;; (e) a second platform coaxial with said first platform and carrying a second plurality of upper filament stock carrying spools, said second plurality being mounted for idle rotation, and said second platform being adapted for rotating in a substantially horizontal plane above said first platform and in the opposite direction thereto, such as to drive said second spool purality to rotate, said filament stock carrying spools of said first and second platforms cooperating function-wise together to form said braid on said coaxial cable; (f) motor and guiding means function-wise arranged between said first and second reels and adapted for picking up said cable stock to be covered from said first reel and guiding said covered cable on said second reel;; characterized in that it comprises filament stock feeding means movable with swinging reciprocating motion in synchronization with the rotary movement of said first and second reels and of said first and second platforms, said filament stock feeding means being effective to feed said filament stock of said lower spools while avoiding the filament stock from the upper spool thereby forming said braid.

2. A braiding machine according to Claim 1, characterized in that said filament stock feeding means include a plurality of filament stock feeding fingers, the movement of each filament stock feeding finger being synchronized with the rotation of said first and second platforms through camming means.

3. A braiding machine according to Claim 2, characterized in that said camming means include a first hollow cam having a plurality of rises and descents for controlling said upper spools and a second lower cam and third lower cam, provided with a plurality of rises and descents, for controlling said lower spools.

4. A braiding machine according to Claim 3, characterized in that said third cam is constantly abutting against a bearing or pivot member effective to drive, through shaft means, means for reciprocating said feeding fingers.

5. A braiding machine according to Claim 3, characterized in that said rises and descents of said first cam are greater in number than said rises and descents of said second and third cams.

6. A braiding machine according to Claim 4, characterized in that said means for reciprocating said feeding fingers include tooth-like elements, there being provided two thereof for each upper spool, the movement of said tooth-like elements being determined by said first hollow cam and by roller means engaging therewith.

7. A braiding machine according to Claim 2, characterized in that said filament stock feeding fingers are actuated through a ring gear, a first gear member idly coupled thereto and rotating in the opposite direction thereto, a pivot element caused to rotate by said idle gear, and a second gear member.

8. A braiding machine according to Claim 7, characterized in that the movement of said filament stock feeding finger is derived from a camming drum formed with a continuous groove.

9. A braiding machine according to Claim 1, characterized in that said first spool plurality comprise single or individually mounted spools.

10. A braiding machine according to Claim 1, characterized in that said lower spools are set at an angle of substantially 45 over the rotation plane and attached to carriage elements adapted for running along substantially circular runways.

11. A braiding machine according to Claim 1, characterized in that said distributing means include a reversing mechanism adapted for reversing the movement thereof at end-of-travel positions.

1 2. An improved rotary braiding machine, substantially as herein described with reference to the accompanying drawings.

1 3. Any novel element, or combination of elements, herein described and/or shown in the accompanying drawings, irrespective of whether the present claim is within the scope of, or relates to the same invention as, any of the preceding claims.