GB2043519A - A circle cutter for cutting a round piece from a sheet material - Google Patents

Abstract

A circle cutter comprising a body 20 bearing a blade member 16, said blade member 16 being movable diametrally about a central axis 300 to effect cutting. A pressure pad 72 is disposed at the lower-most end of the central axis which pressure pad has a contact surface for engagement with the sheet material. Said contact surface may comprise a high-friction material. The pressure pad enables circles to be cut from a sheet material without any damage to the cut circle. <IMAGE>

Description

SPECIFICATION A circle cutter for cutting a round piece from a sheet material This invention relates to a circle cutter for cutting a round piece from a sheet material, for example paper, vinyl sheet or carpet.

Cutters for this purpose are already known from the Japanese Official Gazettes for laying open of utility model No: 119586/77, 23089/78, No: 23090/78 and No: 24590/78.

However all the cutters of the prior art use a sharp needle to locate the centre point for cutting and hence it is necessary to pierce the needle into a material for accurate cutting to be effected.

This is not inconvenient if the circle is not itself required; only the residual portion of the material being retained. If the cut circle must be retained, however, for instance in the case of circularly cutting a printed paper or a photograph, the pin hole made by the needle point will spoil the beauty of the material.

The needles of the circle cutter of the prior art are fitted to a circular foot body or an adjusting nut of the main body so as to be adjustable for height and depth.

In some kinds of the cutters a lock nut or a compression spring may be used to assure the fixation of the needle. If the main body is rotated in a cutting process, the needle rotates with the main body. In which case unskillful rotation may cause a deviation of the needle centre or an enlargement of the pin hole. If the centre of the circle is not discrete, the sheet material cannot be cut in an exact circle.

Of course in the prior art shown in the Japanese Official Gazette for laying open of utility model No: 23089/78 or No: 24590/78, it may be possible to rotate only the main body, fixing the needle by manually pressing the head thereof. However, in this case the main body will rise or fall depending upon the pitch of the screw about which it rotates, and thus the sheet material cannot be cut exactly at the same depth.

These are the failures of the prior art.

The present invention seeks to overcome these deficiencies.

According to the present invention thereore there is provided a circle cutter adapted for positioning on a sheet material and comprising a blade member movable diametrally about a central axis to effect said cutting; and a pressure pad disposed perpendicularly of said central axis and having a planar portion for contact with said sheet material in use, the arrangement being such that said blade member is movable diametrally with respect to the said pad while said pad is being maintained in a predetermined position on said sheet material.

The above and other objects and features of the invention will appear more fully hereinafter from a consideration of the following description taken in connection with the accompanying drawings wherein some examples are illustrated by way of example.

Figure 1 is a plan view of a circle clipping cutter embodying the present invention.

Figure 2 is a sectional elevation taken substantially along the lines ll-ll of Fig. 1.

Figure 3 is a bottom plan view of the cutter.

Figure 4 is a right side view of the cutter.

Figure 5 is a left side view of the cutter where a shaft body is at a lower position.

Figure 6 is an enlarged sectional elevation taken substantially along the line VI-VI of Fig.

1.

Figure 7 is an enlarged sectional side elevation taken along the line VII-VII of Fig. 1.

Figure 8 is an enlarged sectional view taken on line VIll-VIll of Fig. 1.

Figure 9 is an enlarged bottom plan view of a rear part of a main body of the cutter.

Figure 10 is a enlarged sectional view around shaft bodies where a foot part of a first shaft body contacts with a sheet material.

Figure ii is a enlarged sectional view around shafts bodies where a edge of a second shaft body contacts with a sheet material.

Figure 12 is a enlarged sectional view around shaft bodies where both the first and the second shaft bodies contact with a sheet material.

Figure 13 is a sectional elevation of a main part of a second embodiment of the invention.

Figure 14 is a sectional elevation of a bottom part of a third embodiment of the invention.

Figure 15 is a sectional elevation of a main part of a forth embodiment.

Figure 16 is a sectional elevation of a bottom part of a fifth embodiment.

Figure 1 7 is a sectional elevation of a main part of a sixth embodiment.

Figure 18 is a sectional elevation of a bottom part of a seventh embodiment.

A circle cutter 10 of this invention comprises a main body 1 2 a shaft body 14 and a cutting apparatus 1 6 fitted directly, or indirectly by another intermediate body, to the main body 12, it is convenient that the cutting apparatus 1 6 is fixed to a slide 1 8 which can slide radially with respect to the main body 12.

A first embodiment of the invention shown by Figs. 1 to 1 2 has a main body consisting of an annular plate 20, a cylindrical flange 22 rising from the inner edge thereof, ribs 24 formed diametrically of the annular plate 20, and a boss 26 positioned at the conjuction of the ribs 24, of (Fig. 6).

Of course the shape of the main body need not be annular.

In this example one set of ribs 24 is utilized as a guide rail 28 for the slide 18. The guide rail 28 comprises parallel double stepped rails 30 in symmetrical array as shown particularly in Fig. 5 and Fig. 8.

An opening is formed through a portion of the cylindrical flange 22 which is shown at the left hand side of Fig. 1.

A hole 34 is formed in the opposed portion of the cylindrical flange 22 to permit the radial movement of slide 1 8.

The outer surface 36 of the cylindrical flange 22 is knurled for convenience in handling.

A screw thread 38 is formed at the outer surface of the boss 26 for engagement with a corresponding thread on nut 42. It is desirable to make all the parts of the main body 1 2 in a single moulded piece from plastics material, for example by an injection moulding process.

The slide 1 8 is arranged to adjust the distance between the shaft body 1 4 and the cutting apparatus 16, ie: to adjust the radius of the round piece to be cut. Therefore no slide 1 8 is needed for a cutter of a fixed radius type.

The first embodiment of the invention exemplifies a cutter of a variable radius type, in which the slide 1 8 is movable along the guide rail 28 formed in the main body 12.

The sectional shape of the slide 1 8 resembles an inverted 'U' shape which rides and slides on the stepped rails 30 as is shown in Figs. 4, 5, 7 and 8. On the upper wall of the slide 1 8 a slit 40 is formed in the longitudinal direction shown in Fig. 1. This slit 40 confines the range of the movement of the slide 1 8 which cannot be separated from the main body 1 2 because it is clamped by the nut 42. In other words the slide 1 8 can move in a range equal to the length of the slit 40, and the slide 1 8 can be locked at any point on the guide rail 28 within the movement range.

The locking device of the slide 1 8 consists of the male screw-thread 38 of the boss 26, a nut 42 fitted therewith and a washer 44 disposed between the slide 1 8 and the nut 42. The slide 1 8 is locked by tightening the nut 42.

In the first embodiment the slide 1 8 which is made of a metal plate is equipped with a cutting apparatus 1 6 at one end.

At the one end of the slide 1 8 a vertical plate 46 is formed (Fig. 6) and a blade supporting piece 48, which is U-shaped in plan view is fitted (Fig. 3), such that the vertical plate 46 contacts only the flat part of the blade supporting piece 48 and both the side flanges 50 of the piece 48 protrude backwardly toward the body 20 further than the vertical plate 46 (ie: toward the right hand in Fig. 3).

A hole 52 and a hole 54 are punched respectively through plate 46 and piece 48, and a bolt 56 is passed therethrough. A tightening nut 58 is then fitted onto the screw part of the bolt 56.

In this example the head 60 of the bolt 56 is partially arcuate, having a planar portion which contacts directly with either of flanges 50 of the blade supporting piece 48 to prevent a rotation of the blade. As shown in Fig.

6 a snap ring 64 is fitted in a groove between the screw threaded part and the non-screw threaded part of the bolt 56 to prevent the bolt 56 separating from the vertical plate 46 and the blade supporting piece 48.

The cutting apparatus 1 6 is inserted between the head 60 of the bolt 56 and the vertical plate 46 and is fixed by tightening the nut 58.

The cutting apparatus 1 6 is shaped as a parallelogram seen in Fig. 8 for example. On both shorter sides of the parallelogram sharp blades 66 are formed. On the upper half of the apparatus 1 6 a protector tube 68 is inserted to assure safe operation during cutting.

The downward projection of the cutting apparatus 1 6 ie: the cutting depth, is adjusted by the operator corresponding to the depth of the sheet material.

In the first example the cutting apparatus is merely clamped. However, other methods are available as disclosed by Japanese utility model No: 23090/78 or No: 24590/78 wherein the cutting apparatus 1 6 can be made to ascend or descend and can be fixed at any desired height by a screw device. Often the latter is more convenient because of easy adjustment of blade depth.

A pocket 70 is formed in one part of the main body 1 2 to hold reserve cutting blades 16, and other attachments, for instance, foot attachments which will be mentioned afterward.

In Figs. 6 and 9 the rear space on the guide rails 28 is utilized for forming the pocket 70, which has a flap 72 at the bottom to form a closure member.

The flat 72 can open by causing suitable deformation at a horizontal bend line 74. A connecting piece 76 formed at the rear end of the flap 72 serves to engage a groove 78 formed as a part of the main body 1 2 (see Fig. 6).

A scale 80 (Fig. 2) is formed on the slide 1 8 and a cardinal point 82 denoting a centre position is engraved on a rib 24 adjacent the scale 80 to show the distance between the shaft body 14 and the cutting apparatus 1 6.

Of course it is also possible to provide that the scale 80 and the cardinal point 82 are reversed.

With regard to the shaft body 14 the minimum necessary condition is that is has a foot with a wide contact surface 84 and it can rotate around a vertical centre line 300 with respect to the main body 1 2 like a second embodiment shown in Fig. 1 3.

In a second embodiment the shaft body 14 consists of a handle 86, a shaft 88 and a foot part 90. The shaft 88 is inserted into a supporting hole 92 disposed vertically through the boss 26 of the main body 1 2 with clearance. The bottom of the foot part 90 is a comparatively wide contact surface 84.

The shaft 88 and the foot part 90 are cut from a suitable metal rod and the handle 86 is made from a plastics material. Both the shaft 88 and the handle 86 are conjoined adhesively, by virtue of an interference fit, or by suitable screw threading.

The contact surface 84 must contact the sheet of material to be cut securely. Therefore the foot part 90 containing it may be made from a material with a high friction coefficient, for instance from rubber or plastics resin.

Further, the contact surface 84 may be knurled or a friction piece 94 with a high friction coefficient may be adjeted on the foot part 90.

For the same purpose it is also convenient to arrange that a friction piece 94 fits into a hollow part 96 formed at the bottom of the foot part 90 as in a third embodiment shown in Fig. 14.

A fourth embodiment of this invention seen in Fig. 15 shows a shaft body 14 movable vertically with respect to the main body 1 2.

A fifth embodiment shown in Fig. 1 6 has a foot piece 90 with a contact surface which is reversably affixed to the shaft 88.

Fig. 1 7 demonstrates a sixth embodiment in which the shaft body 1 4 comprises a first shaft body 98 with a contact surface 84 at the bottom thereof, and a second shaft body 102 which has a sharp bottom point 100 which shaft 102 can move vertically in the first shaft body 98 and can be stopped at any desired height. The shaft bodies 98 or 102 may be alternately used according to the cutting conditions prevailing.

In this embodiment shaft 88 of the first shaft body 98 is hollow and is formed with female screw thread which is adapted for use with a male screw thread of the second shaft body 102. At the upper rim of the shaft body 98 a stopper tube made from polyvinyl chloride is fixed to prevent to hollow shaft 88 from dropping. The handle 86 is fixed at the head of the second shaft 1 02.

A seventh embodiment of this invention is shown in Fig. 1 8. A foot attachment 106 with a contact surface 104 wider than the contact surface 84 of the foot part 90 is affixed preferably by a screw, to the bottom of the foot part 90 to reinforce the applied friction.

The aforesaid shaft body 14 of the first embodiment (Fig. 6) is made by ammalgamat ing the third, fourth, sixth and seventh em bodiments.

The shaft body 14 of the first embodiment comprises a first shaft body 98 and a second shaft body 1 02. The first shaft body 98 is hollow, has a hollow shaft portion 88 of metal, a foot part 90 and a female screw 108 which is formed on lower half of the inner surface of the shaft 88.

A friction body 9 of circular cross section is fitted into hollow part 96 of the foot part 90.

When the shaft 88 of the first shaft body 98 is inserted into the supporting hole 92, a stopper 110 made from a polyvinyl chloride tube is affixed at the upper edge of the shaft 88.

The second shaft body 102 has a handle 86 at the top thereof and a shaft bolt 11 2 depending downwardly therefrom. The bottom of the shaft 112 terminates in a point 100.

The shaft bolt 11 2 engages the female screw 108 of the first shaft body 98.

In said first embodiment a foot attachment 106, wider than the foot part 90 can be added if desired as shown in Fig. 6. The foot attachment 106 also has a hollow portion 11 6 in which a friction piece 11 8 is diposed.

To fix the foot attachment 106 on the first shaft body 98 male screw part 1 20 of the foot attachment 106 is inserted into the female screw 108 and is rotated to attach it to the first shaft body 98.

A small cavity 1 22 is formed in the male screw part 1 20 of the foot attachment 106 to accommodate the point 100 which is engaged by the cavity 1 22. The measures that by reason of this engagement the second shaft body 102 cannot rotate.

The operation of the invention is now explained. The explanation of the operation of the first embodiment will classify the operations of other embodiments.

The first embodiment is a cutter of variable radius type so an operator loosens the nut 42, moves the slider 1 8 to a desired radial position and tightens the nut 42 to secure the slider 1 8. In this preparatory operation the radius or the diameter of the piece to be cut is set easily be utilizing the scale 80 and the cardinal point 82.

By loosening the tightening nut 58, the operator may set the projection depth of the cutting apparatus 1 6 according to the thickness of the sheet material 200 and tighten the nut 58 to fix the cutting apparatus 1 6 to the slider 18.

If the material to be cut is big enough, the foot attachment 106 is affixed as shown in Fig. 6. However, if the material to be cut is small, for instance, the cutting apparatus 1 6 may contact the wide foot attachment 106, it is better to detach the foot attachment 106 as seen in Fig. 10. If a sharp needle is more desirable as a centre, the operator screws down the second shaft body 102 as shown in Fig. 11. If the operator desires to adjust the piercing depth of the point 100 he may set the projection of the point 100 to a desired piercing depth. In this case the point 100 and the contact surface 84 work together as a centre.

Thereafter the cutter is positioned as desired on a sheet material 200 and the operator presses the holding handle 86 downwardly with his hand to ensure a firm contact of the foot part 90, the point 100 or the foot attachment 106 with the sheet material. By this pressing operation the cutter is assured of a stable centre. Then the operator grasps the cylindrical part 22 and rotates the main body around the shaft body 14. The corrugated surface 36 prevents his fingers slipping. By this means a round piece is cut from the sheet material by the cutting apparatus 1 6 fixed to the slider 18.

As the shaft body 1 4 is movable vertically with regard to the main body 12, to some extent an intimate contact between the main body 1 2 and the sheet material 200 is always accomplished, which results in uniform clipping of a round piece.

As already mentioned in detail, by this invention the round piece can be cut out without a point scar. The cutter of the invention need not spoil the beauty of the cut piece.

With respect to the cutter of the variable radius type the operator can cut round pieces of various radii by use of only one cutter.

Therefore, the invention is advantageous because only a simple cutter device is required, where a point scar is permissible, a needle shaft is available as a centre either for use by itself or co-operating with a contact surface.

Claims (12)

1. A circle cutter adapted for positioning on a sheet material and comprising a blade member movable diametrally about a central axis to effect said cutting; and a pressure pad disposed perpendicularly of said central axis and having a planar portion for contact with said sheet material in use; the arrangement being such that said blade member is movable diametrically with respect to said pad while said pad is being maintained in a predetermined position on said sheet material.

2. A cutter according to claim 1 wherein the diametral distance is variable.

3. A cutter according to claim 2 comprising a main body having a sliding portion therein, said sliding portion bearing said blade member at one end thereof, and being movable radially to vary said diametral distance.

4. A cutter according to claim 3 wherein said sliding portion is associated with a scale indicative of said diametral distance.

5. A cutter according to any preceding claim wherein the pressure pad is reciprocally movable along said central axis.

6. A cutter according to claim 5 wherein said pressure pad is fixedly adjustable to a position on said central axis.

7. A cutter according to any preceding claim wherein said pressure pad comprises a high-friction contact surface.

8. A cutter according to any preceding claim wherein the pressure pad is formed of at least two concentric discs.

9. A cutter according to any preceding claim further comprising a needle movable along said central axis.

1 0. A cutter according to any preceding claim comprising a magazine for spare blades.

11. A cutter substantially as hereinbefore set forth and as illustrated in any one of Figs.

1 to 1 8 of the accompanying drawings.

1 2. A method of cutting a sheet material which comprises positioning a circle cutter according to any one of the preceding claims on said sheet material, applying a force to said central axis to urge the same toward said sheet material thereby using said pressure pad into contact therewith, and moving the blade diametrally of said central axis thereby to cut the sheet material.

1 3. A cut sheet material product when produced by the method of claim

12.