US2911772A

US2911772A - Grinding device for cloth cutting machines and the like

Info

Publication number: US2911772A
Application number: US723923A
Authority: US
Inventors: Gronemeier Heinz
Original assignee: HOOGLAND E
Current assignee: E HOOGLAND; HOOGLAND E
Priority date: 1957-03-26
Filing date: 1958-03-25
Publication date: 1959-11-10
Anticipated expiration: 1976-11-10

Description

Nov. 10, 1959 2,911,772

GRINDING DEVICE FOR CLOTH CUTTING MACHINES AND THE LIKE Filed March 25, 1958 H. GRONEMEIER 2 Sheets-Sheet 1 IN VE N TOR A O/IIL QoIrEME/Er Nov. 10, 1959 H. GRONEMEIER 2,911,772

GRINDING DEVICE FOR CLOTH CUTTING MACHINES AND THE LIKE F'iied March 25, 1958 2 Sheets-Sheet 2 //V MENTOR l llll-llllll 9/712 42 em a for @a Unite a GRINDING DEVICE FOR CLOTH CUTTING MACHINES AND THE LIKE Heinz Gronemeier, Bonn-Buschdorf, Germany, assignor to E. Hoogland, Zuschneidernaschinenfabrik, Bonn- Nord, Germany The present invention relates to a grinding device for cloth cutting machines. Heretofore known grinding devices employed for cloth cutting machines are provided with grinding discs or grinding belts which during their grinding operation are passed along the knives to be ground. This type of grinding device has various drawbacks.

Grinding devices operating with grinding discs have the drawback that the cutting angle changes continuously in view of the grinding down of the knives and the wearing off of the grinding discs. In extreme situations, such grinding devices become so dull that the ground cutting edge will not cut any longer. When employing grinding discs, the ground surface of the cutting knives becomes hollow. If the ground surface of the cutting knives is ground hollow, the cutting edge will more or less easily fold over depending on the material of the cutting edge. In addition thereto, the grinding discs become untrue in a relatively short time and crack so that a relatively frequent exchange of the grinding discs will become necessary.

Surfaces ground by grinding belts become crowned due to lack of uniform grain structure or to the shimmying of the grinding belts. A ground crowned cutting edge easily burns out by overheating due to excessive friction.

Due to the wear of the grinding discs and grinding belts during the grinding operation, abrasive powder is formed which enters parts of the device and the guiding means for the knives thereby bringing about a premature wear of these elements. Furthermore, with the heretofore known grinding devices, a burr is formed on the cutting edges of the knives and also a grinding soft zone is formed whereby the maintenance of the proper cut of the knives is greatly afiected.

Finally, the dimensions and arrangement of the heretofore known grinding devices greatly affect the visibility during the grinding operation.

It is, therefore, an object of the present invention to provide a grinding device of the type involved, which will overcome the above mentioned drawbacks.

It is another object of this invention to provide a grinding device for cloth cutting machines, which will pro duce a straight, plane, razor blade sharp V-shaped ground surface with always the same cutting angle.

It is a further object of this invention to provide a grinding device for cloth cutting machines, which will make it possible to grind the cutting knives so as to cause the same always to produce the same cut.

It is a still further object of this invention to provide a grinding device of the type set forth in the preceding paragraphs, which will considerably reduce the wear of the cutting knives to be ground thereby.

These and other objects and advantages of the invention will appear more clearly from the following specification in connection with the accompanying drawings, in which:

Fig. l is a front view of a grinding device according States Patent to the present invention in connection with a vertical cloth cutting machine.

Fig. 2 is a side view of the machine shown in Fig. 1.

Fig. 3 illustrates the grinding unit according to the invention in opened condition.

Fig. 4 shows the grinding unit of Fig. 3 in closed condition.

Fig. 5 illustrates on a somewhat larger scale than Figs. 1 to 4 the front view of the grinding device according to the invention in its grinding position, but with the blocking mechanism for the current supply in open position.

Fig. 5a illustrates a front view of the grinding device during the grinding operation.

Fig. 6 is a side view of the arrangement shown in Fig. 5.

Fig. 7 illustrates the grinding unit itself during the grinding operation.

Fig. 8 illustrates the grinding unit of Fig. 7 with one arm tilted outwardly in order more clearly to show the cutting angle.

General arrangement The grinding device according to the present invention is characterized primarily in that the grinding elements comprising diamond chips or diamond dust bound ceramically or by vegetable or mineral binding means are arranged in supports which are adapted to press the grinding elements against the cutting edge of the cutting knife in such a way that the diamond chips or the diamond dust acts upon said cutting edge.

The supports for the grinding elements may, in conformity with the present invention, be mounted on plierlike rod-shaped arms tiltable in a horizontal plane about a pivot. These arms are adapted by pull or by pressure, for instance by a tension spring connected to said arms, to be pressed from both sides against the cutting edge of the knife.

The device according to the present invention will produce a straight, plane, razor blade sharp ground surface of V-shape which will always have the same angle and a proper fine surface. The surface quality corresponds to that of a lapped cutting edge.

The maintenance of the cut of the knife as well as the precision of the cut is dependent on the quality of the surface of the knife.

The grinding device according to the present invention, therefore, brings about a considerable improvement in the surface quality of the ground cutting edge of the knife and Will produce a cutting edge which will last considerably longer than cutting edges produced with heretofore known grinding devices for the purpose involved. The new grinding device or, more specifically, the cut produced thereby, will prevent the danger that threads are pulled out of the fabric while it is being cut by the cutting knife. Experience has proved that the grinding device according to the invention reduces the wear of the knifeto one quarter and even one sixth of the wear of knives ground by heretofore known grinding devices.

The grinding elements of the grinding device according to the present invention are for all practical purposes not subjected to any wear at all so that an exchange of these grinding elements is hardly ever necessary. The harmful formation of abrasive dust will be avoided. A change of the original grinding angle due to the wear of the grinding element will likewise be avoided.

A further feature of the grinding device according to the invention consists in that the supports for the grinding elements are tiltable about a vertical axis for adjusting any desired grinding angle so that it will be possible to adjust the grinding angle in a manner which is most favorable for the respective fabric to be cut.

Structural arrangement Referring now to the drawings in detail, Figs. 1 and 2 illustrate a cloth cutting machine 2 mounted on a foot 1 and provided with a vertical knife 3 to be ground .by a grinding device 4 according to the invention. The grinding device 4 is mounted on the cover 5 of the cutting machine 2. The grinding device 4 is designed as independent unit equipped with its own driving motor 6 and is adapted easily to be mounted on any cloth cutting machine.

The grinding device is driven by motor 6 which preferably represents a reversible electric motor. This drive is effected through a transmission 7 which in its turn drives a threaded spindle in the housing of the grinding device 4. Mounted on the threaded spindle is a nut (not shown in the drawing) which carries a tubular guiding element 8 and brings about the upward and downward movement of said guiding element 8. The lower end of the guiding element 8 carries the grinding unit proper. As willbe evident from Figs. 3 and 4, the said grinding unit comprises plier-like tiltable supporting

arms

9, 9a. The front ends of said

arms

9, 9a have angularly adjustably mounted thereon

holding elements

11, 11a for the

grinding elements

12, 12a so that the latter can be adjusted relative to each other in conformity with a desired variable grinding angle 10. The grinding angle is adjusted by turning the holding elements '11, Ha for the

grinding elements

12, 12a about the pivots 24, 24a respectively. After the angle 10 has thus been adjusted, the

holding elements

11, 11a are held in their respective position by any convenient means as for instance set screws or clamping screws. The

arms

9, 9a are adapted to straddle a rod 14 which carries the pressing element 13 for the cloth to be cut, and are also adapted to press the

grinding elements

12, 12a against the knife 3. When the grinding unit occupies its upper position, the holding

arms

9, 9a are tilted away from each other by the

abutment cam members

15, 15a so that the said arms will not impair the visibility during the cutting of the cloth. This represents a considerable advantage over the heretofore known grinding devices of the type involved, in which due to mechanisms of considerable dimensions, for instance by drives mounted in the holding arms for driving the grinding discs, the visibility is greatly impeded.

The drive for the knife of the cutting machine is controlled by a switch 17 (see Fig. 2). A push button switch 16 (see Fig. 1) controls the operation or standstill of the grinding device.

The supply of current to the grinding device is interrupted as long as the cloth pressing element 13 does not occupy its lowermost end position in order to prevent the grinding unit from moving against the pressing element 13.

Figs. 5, 5a and 6 illustrate a blocking mechanism which comprises two

resilient contact arms

18, 18a with

contacts

19, 19a. These contacts are pressed against each other and thereby closed in the end position only of the pressing element 13. This pressing of the

contacts

19, 19a against each other is effected by a bolt 20 connected to the rod 14 supporting the pressing element 13. It is only when said

contacts

19, 19a have been closed (Fig. 5a) that the guiding element 8 of the grinding unit can start its downward movement. During this downward movement, the

arms

9, 9a will due to the effect of the tension spring 21 slide along the

cams

15, 15a until the

grinding elements

12, 12a due to the force of the tension spring 21 are pressed at a grinding angle determined by the adjustment of the holding

elements

11, 11a against the cutting edge 22 of the quickly reciprocating knife 3 as shown in Figs. 7 and 8.

In conformity with the specific showing of Figs. 5 and 8, the grinding

elements

12, 12a are so arranged that one. holding arm 9a has at 24a pivotally connected thereto a holding element 11a with two grinding elements 12a at a distance corresponding to their height, whereas the other holding arm 9 pivotally supports at 24 a holding element.-

limit switch so that the. stroke of the grinding unit in the respective opposite direction will be initiated.

The longitudinal axis 23 of the grinding device according to the invention and more specifically of the guiding element 8 is slightly inclined relative to the vertically arranged knife 3. This inclination is such that during the upward stroke of the grinding device the grinding

elements

12, 12a move toward the knife 3. This move ment of the grinding elements toward the knife will prevent the formation of burr normally occurring during all grinding operations. Furthermore, the grinding

elements

12, 12a will be under uniform load so that a linear grinding-in or grooving will be possible with the arrangement according to the invention. about a further improvement of the surface of the cutting edge 22.

It is, of course, to be understood that the present invention is, by no means, limited to the particular construction shown in the drawings but also comprises any modification within the scope of the appended claims.

What I claim is:

1.,In combination with a cloth-cutting machine having a vertical knife with a cutting edge: a vertically reciprocable member, holding means supported by said reciprocable member, grinding bodies mounted in said holding means and angularly adjustable relative to each other so as to form different desired angles with each other, said grinding bodies being composed of diamond chips bonded to each other, said holding means being tiltable in a substantially horizontal plane about said reciprocable member and being operable to press said grinding bodies against the cutting edge of said knife for grinding the same, and means for reciprocating said reciprocable member in the longitudinal direction of said knife.

2. An arrangement according to claim 1, in which the diamond chips are bonded by ceramic binding means.

3. An arrangement according to claim 1, in which the diamond chips are bonded by vegetable binding means.

4. An arrangement according to claim 1, in which the diamond chips are bonded by mineral binding means.

5. In combination in a grinding device for grinding the cutting edge of a vertically arranged knife of a clothcutting machine: a vertically reciprocable member, a pair of holding arms pivotally supported by said reciprocable member, both of said holding arms being tiltable about the axis of said reciprocable member toward or away from each other and said knife, a pair of holding members respectively pivotally supported at the free ends of said arms so that each of said holding members is tiltable and adjustable about a substantially vertical axis thereby making it possible to adjust and maintain said holding members at a different desired angle with regard to each other, grinding bodies mounted in said holding members and movable by said arms into grinding engagement with opposite sides of said knife, and means for reciprocating said reciprocable member to thereby cause said grinding bodies when in engagement with said knife to exert a grinding action thereupon.

6. In combination with a cloth-cutting machine having a vertically extending knife with a cutting edge: a reciprocable member, holding means supported by said reciprocable member, grinding bodies mounted in said holding means and composed of diamond chips bound to each other, said holding means being operable to press said grinding bodies against the cutting edge of said knife This brings a 5 for grinding the same, first motor means for actuating said knife, second motor means independent of said first motor means for reciprocating said reciprocable membet in the longitudinal direction of said knife, a clothpressing member adjustably mounted in said cloth-cutting machine, and contact means arranged to control the operation of said second motor means, said contact means normally being in open position to thereby prevent oper- References Cited in the file of this patent UNITED STATES PATENTS Maimin Apr. 25, Babcock et a1. May 1, Barton July 18, Langman May 3, Maiman Sept. 12, Maiman Sept. 26, Root -7 June 20,

Siegel Aug. 7, Draper Mar. 4, Price Sept. 26,