Knitting machine

Abstract

A cam for a circular knitting machine has at least one cam groove formed in a cam surface to receive and guide a foot of a stitch-forming tool with which the cam is intended to operate. Additional recesses are formed in the cam surface to reduce the striking surface between the cam surface and a shank of the stitch-forming tool.

Description

CROSS-REFERENCE TO A RELATED APPLICATION

The invention described and claimed hereinbelow is also described in German Priority Document DE 10 2013 208066.2, filed on May 2, 2013. The German Priority Document, the subject matter of which is incorporated herein by reference, provides the basis for a claim of priority of invention under 35 U.S.C. 119(a)-(d).

BACKGROUND OF THE INVENTION

The present invention relates to a cam for a circular knitting machine with at least one cam groove formed in the cam surface to receive and guide a foot configured on a stitch-forming tool.

Cams of circular knitting machines are not only for raising the stitch-forming tools for the stitching-forming operation. Cams of circular knitting machines also hold the stitch-forming tools in their position with their surface. In this way, for example, the cams prevent the cylinder needles of a circular knitting machine from being swung radially outwards by the centrifugal forces that arise during rotation of the cylinder. In plain circular knitting machines, the sinker cams prevent the down sinkers from tilting as a result of the action of force of the stitches.

In all these cases, the stitch-forming tools are pressed against the cam surfaces. Since the stitch-forming tools move relative to the cams, friction forces thus arise that lead to a premature wear of the stitch-forming tools in particular. Moreover, the friction causes a considerable development of heat and demands a higher energy requirement of the drive of the machine. Therefore, the cams are lubricated in order to keep the friction energy as low as possible.

SUMMARY OF THE INVENTION

The present invention overcomes the shortcomings of known arts, such as those mentioned above.

To that end, the present invention provides cams in which the friction between their surface and stitch-forming tools with which the cam or knitting machine are intended to be used is reduced.

In an embodiment, the invention provides a cam fora circular knitting machine with at least one cam groove formed in its surface to receive and guide a foot configured on a stitch-forming tool. The cam groove is characterised in that additional recesses are formed in the cam surface to reduce the striking surface between the cam surface and the shank of the stitch-forming tools.

In this case, the stitch-forming tools that are guided in at least one cam groove are any of the group consisting of needles, control sinkers, down sinkers, swivel sinkers, spring sinkers, spring pins, intermediate pins and jack selectors, for example, without limitation.

The recesses in the cam surface not only cause the abutment surfaces between the cams and the stitch-forming tools to be reduced and thus the friction to be reduced, but also cause the flow of the lubricant on the cam surface to slow down. The oil collects in the recesses, which thus form oil reservoirs for an improved lubrication. As a result, the friction between the stitch-forming tools and the cam surface is further reduced, and thus less wear and less heating up of the stitch-forming tools occur. Moreover, the need for lubricant is reduced with the invention.

For that matter, the inventive cams are individualised in a manufacturer-specific manner and distinguished more easily from copies by the type of recesses.

In a cam embodiment, the cam recesses are channels or grooves, which extend in the running direction of the stitch-forming tools with which the cam or knitting machine are intended to be used. These recesses can slow down the flow of the lubricant on the cam surface from top to bottom over the entire width of the cam. In this case, the channels or grooves preferably run parallel to the at least one cam groove, as a result of which the cam surface is provided very uniformly with friction-reducing recesses.

In an embodiment, the channels or grooves can extend in a star shape from an oil nozzle outlet. The oil is transported upwards from below in these grooves and the oil consumption can thus be reduced.

Intersecting channels or grooves also can be used to enable the oil to be evenly distributed. However, other configurations of the recesses are also usable, e.g., such as cylindrical, arrow-shaped or trough-shaped recesses arranged in a uniform grid, without limitation.

In this case, the depth of the channels or grooves can decrease or otherwise vary in the running direction of the stitch-forming tools. As a result of this measure, a pumping action is generated for the oil collecting in the recesses and the lubrication effect can thus be improved.

A further reduction in friction between the cam and the stitch-forming tools is achieved in that the cam surface between the recesses is convex at least in regions. This results in merely punctiform abutment points between the stitch-forming tools and the cams. Oil can collect in the recesses.

It also is possible to provide multiple recesses of different shapes in a cam.

In the cam embodiment provided with grooves or channels running parallel to the cam groove, a stitch-forming tool is used that is preferably provided with a flat projection on its shank that is inserted into one of the grooves or channels. The projection preferably runs in the groove or channel without touching. A cam without the groove to fit the projection cannot then be operated with this stitch-forming tool. Copying of cams can thus be made more difficult.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the invention will become apparent from the description of exemplary embodiments that follows, with reference to the attached

Figs, wherein:

FIG. 1 presents a perspective view of a first cam;

FIG. 2 presents a perspective view of a second cam;

FIG. 3 presents a perspective view of a third cam;

FIG. 4a presents a perspective view of a fourth cam;

FIG. 4b presents a perspective view of a fifth cam;

FIG. 5a presents a perspective view of a sixth cam;

FIG. 5b presents a view from above onto the cam depicted in FIG. 5a;

FIG. 6 presents a perspective view of a seventh cam;

FIG. 7 presents a perspective view of an eighth cam;

FIG. 8 presents a perspective view of a ninth cam;

FIG. 9a presents a perspective view of a further production variant of the cam depicted in FIG. 3;

FIG. 9b presents a perspective view of a further production variant of the cam depicted in FIG. 3;

FIG. 9c presents a perspective view of a further production variant of the cam depicted in FIG. 3; and

FIG. 10 presents a perspective view of the cam depicted in FIG. 1 with a stitch-forming tool.

DETAILED DESCRIPTION OF THE INVENTION

The following is a detailed description of example embodiments of the invention depicted in the accompanying drawings. The example embodiments are presented in such detail as to clearly communicate the invention and are designed to make such embodiments obvious to a person of ordinary skill in the art. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present invention, as defined by the appended claims.

FIG. 1 presents a cam 10 of a circular knitting machine (not further shown) to include a cam groove 11 for guiding a foot 12 of a stitch-forming tool 13, one embodiment of which is shown in FIG. 10. The course of the cam groove 11 depends on the raising arid return movements that the stitch-forming tool 13 is configured to perform. Two recesses 14, 15 in the form of broad shallow grooves are moulded into the surface 16 of the cam 10 parallel to the cam groove 11. The two recesses 14, 15 serve to reduce the striking surface between the surface 16 of the cam 10 and the shank of the stitch-forming tool 13 (FIG. 10). Moreover, the two recesses 14, 15 serve to slow down the flow-off of lubricant on the surface 16 of the cam 11 in the direction of arrow 18. The lubricant is partially collected in the recesses 14, 15, which thus form a lubricant reservoir. The depth of the recesses 14, 15 can vary in the running direction, the direction of arrow 19, of the stitch-forming tools 13 in this case.

FIG. 2 shows a second exemplary embodiment of a cam 20, which besides the cam groove 21 is provided with channel-shaped recesses 22 running parallel thereto in its surface 26. Like the groove-shaped recesses 14, 15 of the cam 10 (FIG. 1), the recesses 22 of cam 20 also ensure a reduction of the contact surface between a stitch-forming tool 13 and the surface 26, as shown. At the same time, lubricant running downwards on the surface 26 is partially collected over the entire width of the cam 20. The resulting friction between the stitch-forming tools 13 and the cam 20 is thereby reduced, the lubricant requirement decreased and the energy requirement of the drive of the circular knitting machine lowered.

In contrast to the configurations of FIGS. 1 and 2, the cam 30 shown in FIG. 3 has a plurality of blind hole-type recesses 32 arranged in a uniform grid and a groove 31. These blind hole-type recesses 32 are suitable for reducing the striking surface between the stitch-forming tools 13 and the cam 30 and collect lubricant flow-off.

FIGS. 4a and 4b show respective cams 40 and 45, each with respective arrow-shaped recesses 41, 42. Recesses 41 extend in the cam running direction 43 and recesses 42 extend in the opposite direction. Recesses 41, 42 form an oil reservoir. Moreover, recesses 41, 42 are substantially conical in shape so that a kind of pumping effect is achieved for the oil with recesses 41. The recesses 42 directed in the opposite direction serve as receiver for excess oil. A trough shape also may be selected for recesses 41, 42, instead of an arrow or conical shape.

FIGS. 5a and 5b show a cam 50 (FIG. 5b presents a view from above onto the cam depicted in FIG. 5a), in which the recesses 51 are configured such that hump-shaped raised areas 52 provide the contact surfaces with the stitch-forming tools. As a result, friction between the stitch-forming tools and the cam surface only occurs at punctiform areas. In order to assure a uniform guidance of the stitch-forming tools, the hump-shaped raised areas 52 also may be staggered relative to one another.

The cam 60 is shown in FIG. 6 to have grooves 62 as recesses that extend in a star shape from oil inlets or outlets 61. All the grooves 62 extend upwards in the running direction 63 of the cam 60. As a result, the oil is transported from the bottom upwards in the grooves and the oil consumption can thus be reduced. In the opposite running direction of the cam 60 the grooves 62 are used for oil flow out of the cam 60.

FIG. 7 shows a further cam 70 with horizontally running groove-shaped recesses 71. Cam 70 is distinguished, as shown, and by an extremely simple manufacture.

In contrast, FIG. 8 shows a cam 80 with intersecting rectilinear grooves 81 as recesses. This course of the grooves 81 enables the oil to be evenly distributed over the cam surface.

FIG. 9c shows a cam 30′, which is a variant of the cam 30 depicted in FIG. 3. In contrast to cam 30, cam 30′ is not produced in one piece, but from a base plate 35 (FIG. 9a) and two shell parts 36a, 36b (FIG. 9b). A cam groove 31 is formed in the base plate 35 for the foot of a stitch-forming tool (not shown). The two shell parts 36a, 36b are provided with blind hole-like recesses 32 and are fastened to the base plate 35 in such a manner that the cam groove 31 is exposed between the shell parts 36a, b. In the case of thicker shell parts 36a, 36b, the cam groove 31 also may be configured exclusively between the shell parts 36a, 36b or, in a single-part shell part. Therefore, different shell parts 36a, 36b can be arranged on a uniform base plate 35 and the costs for production of the cam 30 are reduced.

Recesses 14, 16, 22, 32, 41, 42, 51, 62, 71, 81, included in cams 10 to 80, also may be used to individualise the cams of a manufacturer and render it more difficult for unauthorised copies to be fabricated. This protection against copying is further increased if the stitch-forming tools 13 are matched individually to the cam, for example, cam 10 or its recesses 14, 15, as made clear in FIG. 10. Therein, cam 10 with the recesses 14, 15 together with a stitch-forming tool 13 is shown once again. As usual, the stitch-forming tool 13 has a foot 12, which is guided in the cam groove 11 and thus assures the raising and return movements of the stitch-forming tool 13. In addition, the stitch-forming tool 13 is provided with a projection 17, which engages into the groove-shaped recess 14 and moves along this in a friction-free manner when the foot 12 is moved along the cam groove.

The stitch-forming tool 13 is thus matched exactly to the cam 10 and cannot be used together with other cams, e.g., the cams 20, 30 or conventional cams without recesses in the surface.

As will be evident to persons skilled in the art, the foregoing detailed description and figures are presented as examples of the invention, and that variations are contemplated that do not depart from the fair scope of the teachings and descriptions set forth in this disclosure. The foregoing is not intended to limit what has been invented, except to the extent that the following claims so limit that.

Claims

1. A cam fore circular knitting machine, comprising:

at least one cam groove formed in a cam surface to receive and guide a foot configured on a stitch-forming tool, with which stitch-forming tool the cam is intended to operate; and

one or more recesses formed in the cam surface to reduce a striking surface between the cam surface and a shank of the stitch-forming tool.

2. The cam according to claim 1, wherein the one or more recesses embody channels or grooves that extend in a running direction of a stitch-forming tool with which the cam is intended to operate.

3. The cam according to claim 2, wherein the channels or grooves extend parallel to the at least one cam groove.

4. The cam according to claim 1, wherein the cam further comprises an oil outlet nozzle and wherein one or more recesses are channels or grooves that extend in a star shape from the cam oil nozzle.

5. The cam according to claim 1, wherein the one or more recesses are intersecting grooves or channels.

6. The cam according to claim 1 wherein the one or more recesses are cylindrical, arrow-shaped or trough-shaped in configuration.

7. The cam according to claim 1, wherein the depth of the one or more recesses varies in a running direction of stitch-forming tools with which the cam is intended to operate.

8. The cam according to claim 1, wherein the cam surface between the one or more recesses is convex at least in regions.

9. The cam according to claim 1, wherein the cam is formed by a base plate, on which at least one shell part forming the cam surface is arranged.

10. The cam according to claim 1, wherein one or more stitch-forming tools which are intended to be guided in the at least one cam groove are any of the group of stitch-forming tools consisting of needles, control sinkers, down sinkers, swivel sinkers, spring sinkers, spring pins, intermediate pins and jack selectors.

11. Stitch-forming tool configured for operation with a cam for a circular knitting machine, the stitch-fitting tool comprising a shank having a foot and a flat projection;

wherein the cam comprises at least one cam groove formed in a cam surface to receive and guide the foot of the stitch-forming tool; and one or more recesses formed in the cam surface to reduce a striking surface between the cam surface and the shank of the stitch-forming tool that embody channels or grooves that extend in a running direction of the stitch-forming tool; wherein the channels or grooves extend parallel to the at least one cam groove and wherein the flat projection inserted into one of the grooves or channels.

12. The stitch-forming tool according to claim 11, wherein the cam is formed by a base plate, on which at least one shell part forming the cam surface is arranged and wherein the projection runs in the groove or channel without touching.