Full metal cutter knife

The present invention provides a cutter knife, which even if made with only the metal parts, smoothness of sliding operation of the blade is not degraded in time, even without lubricating oil nor friction resistant coating, A slider of the cutter knife carries rolling member, which is made rolling contact with the outer surface of the cutter knife. Further, the slider has a protrusion which extends into the cutter knife body and is engaged into a hole formed on the blade. Since an external force applied onto the slider is received by the rolling member, the slider can be operated smoothly. Besides, the height of the protrusion is determined, such that the protrusion does not touch the inner surface of the cutter knife. Thus, the protrusion tip never interfere with the inner surface of the cutter knife, thereby the sliding operation of the slider would not be prevented.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention is related to a cutter knife, which can be surely prevented from being entered into other products as a foreign substance.

Description of the Related Art

For example, regarding products of mattress or stuffed toy animal, sometimes a cutter knife used during manufacturing process may remain in the products as a foreign substance. The cutter knife as the foreign substance is to be found by a metal detector and taken out.

For surely being found by a metal detector, the cutter knife may preferably include many metal components. Theoretically, even a common cutter knife, the body of which is made of plastics, could be found by a metal detector, because the blade of which is made of metal. But actually, a cutter knife having less metal components could pass by the metal detector, without being found.

In order to optimally be found by the metal detector, the whole of a cutter knife including its body would be all made with metal parts. The cutter knife made with only metal parts has been already put on the market by the applicant, and was also published in a Japanese magazine of Weekly MAINICHI-GRAPH of Oct. 7, 1979.

However, if the whole of a cutter knife is made with metal parts only, there may be a problem, that is, smoothness of sliding operation of the cutter knife blade could be degraded in time because of friction and the like, particularly in a type of a cutter knife wherein its blade is extended and retracted in a sliding manner. In order to prevent this, lubricating oil or friction resistant coating may be applied, but it could bring another problem, below.

That is, because of the lubricating oil, products of mattress or stuffed toy animal could get dirty, or otherwise, there may be a sanitary problem when the cutter knife is used in the field of foods. Further, applying the friction resistant coating could increase the manufacturing cost.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a cutter knife, having a blade within its body slidably extended from or retracted into the body, in which even if the cutter knife is made with only the metal parts, smoothness of sliding operation of the cutter knife blade is not degraded in time, even without lubricating oil or friction resistant coating.

In order to achieve the objects of the present invention, there is provided a cutter knife comprising:

a cutter knife body,

a knife blade, which is slidably held in the cutter knife body, and

a slider, via which the knife blade is operated to extend from or retract into the cutter knife body,

wherein at least one of the knife blade and the slider is supported, at a position where the knife blade and/or the slider is made contact with the cutter knife body, by a rolling member which reduces frictional interference.

Note that, in the present invention, the word “rolling member” means anything, with which frictional interference can be lowered taking advantage of its rolling action, for example, a column, a cylinder, a sphere or the like.

With the cutter knife of the present invention, constructed as above, regarding the knife blade and the slider, which slide relatively to the cutter knife body, at least one of which (preferably both) is supported by a rolling member which reduces frictional interference, at a position where the knife blade and/or the slider is made contact with the cutter knife body.

Thus, even if the whole of the cutter knife is made with metal parts only, without lubricating oil nor friction resistant coating, the smooth sliding operation of the slider can be realized for long time in use.

In other words, by making the cutter knife with metal parts only, the cutter knife would be surely sensed by a metal detector. Furthermore, without lubricating oil nor friction resistant coating, the smooth sliding operation of the slider can be realized for long time in use.

Thus, thanks to the present invention, a cutter knife, of which the smooth operation is not degraded for long time in use, can be made with metal parts only, and thus, such the cutter knife can be surely sensed by a metal detector.

But note that, in the present invention, it is not necessary needed to make the cutter knife with 100% only metal parts, and partially other materials could be used in some portion of the cutter knife to some extent, as long as actually no problem is brought.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Before the description of the embodiments proceed, it is to be noted that like or corresponding parts are designed by like reference numerals throughout the accompanying drawings.

Referring toFIGS. 1A to 4, a description is made below on a cutter knife10, according to the first embodiment of the present invention.

First Embodiment—General Construction of the Cutter Knife10

FIGS. 1A and 1Bshows the cutter knife10. InFIG. 1A, the blade20is retracted into the cutter knife body11, and inFIG. 1B, the blade20is extended from the cutter knife body11.

A user operates the slider30, which is mounted outside of the cutter knife body, to extend the blade20from the cutter knife body11and to retract the blade20into the body11. The slider30is being urged in the direction of retracting the blade20, by the spring40mounted inside the cutter knife body11(seeFIG. 2), such that when the user releases his/her finger from the slider30, the blade20is always to be retracted into the cutter knife body11(seeFIG. 1A).

FIG. 2is an exploded view of the cutter knife10. The cutter knife body11is a sleeve-like, within which the blade20can slide in the longitudinal direction. The slider30is mounted outside the cutter knife body11, such that the user can operate the slider30with his/her finger. In the shown embodiment, the slider30is integrally formed with an elongated sliding member31at its forward end, which is mounted inside the cutter knife body11.

The cover member45is to be attached to the cutter knife body11, such that the cover member45extends over the sliding member31. Thanks to this cover member45, the smooth sliding operation of the sliding member31is ensured, even when the cutter knife10is grasped in hand.

The sliding member31and the cutter knife body11are connected with each other by the spring40. With the spring force of the spring40, the slider30is urged in the direction of retracting the blade20. That is, as shown inFIG. 2, one end of the spring40is retained at the hook12of the cutter knife body11, and the other end of the spring40is retained at the hook32of the sliding member31.

First Embodiment—Connecting Manner Between the Slider30and the Blade20

As best shown inFIG. 3of a sectional view in longitudinal direction, the slider30has protrusions35,36on the sliding member31, extending in the cutter knife body11. These protrusions35,36are engaged into the holes25,26formed on the blade20, such that the slider30and the blade20can slide together.

The height of the protrusions35,36is determined, such that their tips35a,36ado not touch with the inner surface15aof the cutter knife body11in an assembled up condition of the cutter knife10. Thanks to such the construction, when the slider30slides along with the cutter knife body11, the protrusion tips35,36are surely prevented from interfering with the inner surface15aof the cutter knife body11, and thus realizing the smooth sliding operation.

Note that although in the shown embodiment two protrusions35,36are made engaged into the holes formed on the blade, the number of the protrusions can be conveniently selected.

FIG. 4is a bottom perspective view, showing the back side of the slider30and the sliding member31. InFIG. 4, in order to better show the configuration of the slider30and the column50which is rotatably held thereto, partially enlarged views are also shown therein.

In the shown embodiment, the slider30is a member having a cross sectional view of U-shape, which comprises the top wall30aand opposed two side walls30b,30c, and in which the space of U-shape, a column (rolling member)50is carried so as to freely roll. In order prevent unwillingly fall off of the column50from the slider30while allowing the column50to freely roll, there are provided stop walls30d,30eat the both ends of the top wall30a, and the receiving wall30fat the lower end of the side wall30b.

First Embodiment—Mechanism for Realizing the Smooth Slide Operation of the Slider30

Generally speaking, when operating the slider30with a finger, gripping the cutter knife10in hand, the external force applied from the finger to the slider30will act in the direction of pushing the slider30onto the outer wall of the cutter knife body11(arrow “A”,FIG. 3). In the cutter knife10of the present invention, such the external force is received by the column50which is contacting with the outer wall of the cutter knife body11, and which is carried so as to freely roll. Thus, the column50will roll on the outer wall of the cutter knife body11, and thereby the slider30can be smoothly operated to slide.

The heights of the protrusions35,36which connect the slider30and the blade20are designed, such that their tips35a,36ado not reach the inner surface15aof the cutter knife body11. Thus, even if an external force is applied onto the slider30in the direction of the arrow “A” inFIG. 3, the protrusions35,36do not touch the inner surface15a, and thus the smooth sliding operation of the slider30is not to be prevented.

Further, since such the protrusions35,36are engaged into the holes25,26formed on the blade20to connect the slider30and the blade20, the external force “A” (FIG. 3) applied on the slider30is never propagated to the blade20. Therefore, the blade20is never pressed onto the inner surface15aof the cutter knife body11(and the inner surface therearound) to generate friction.

Thanks to the above factors (I)-(III) together, in the present invention, even if the whole of the cutter knife is made with metal parts only, the smooth sliding operation of the slider30(that is, smooth extending out and retracted into) can be realized for long time in use. For that, lubricating oil or friction resistant coating is not needed.

Thus, thanks to the present invention, a cutter knife, of which the smooth operation is not degraded for long time in use, can be made with metal parts only, and thus, such the cutter knife can be surely sensed by a metal detector. Note that it is not necessary needed to make a cutter knife with 100% only metal parts, and partially other materials could be used.

Variant of the First Embodiment

In the shown embodiment, a column is employed as the rolling member50and its rolling action is taken advantage of. But, as long as the same effect is obtained, a cylindrical member, a spherical member and the like can be used. Depending on the specific configuration of the rolling member, the configuration of the slider30would be changed, such that the rolling member is carried so as to freely roll while unwilling fall off of the slider30is prevented.

in the shown embodiment, the wall15, which is opposed to the wall on which the slider30is mounted, is raised outwardly, and due to such the raise the inner surface15aof the cutter knife body11is depressed outwardly. The protrusion tips35a,36aterminate in the space16formed by the depression, and thanks to this, the protrusion tips35a,36aare prevented from interfering with (touching) the inner surface15aof the cutter knife body11. Simultaneously, thanks to the moderate raise of the wall15, ease of grasping the cutter knife and of handling the same can be improved.

Note that the raise of the wall15is not necessary needed, and for example, the wall15could be made flat and the heights of the protrusions35,36could be adjusted so as not to touch the inner surface of the wall15.

Second Embodiment—the Rolling Member is Located at the Protrusion Tip

FIG. 5shows the cutter knife according to the second embodiment of the present invention, in comparison with the first embodiment. Only the difference of the second embodiment to the first embodiment is the location of the rolling member, and thus the difference is only explained.FIG. 5is one corresponding toFIG. 3, and shows the region around the tip of the protrusion35, enlarged.

In the first embodiment (FIGS. 1A-4), the height of the protrusion35is determined, such that the protrusion tip35adoes not reach the inner surface15aof the cutter knife body11, and thanks to this, interference between the protrusion tip35aand the inner surface15awas prevented.

On the contrary, in the second embodiment, the rolling member50′ is located at the tip of the protrusion35, thereby preventing interference between the protrusion tip35aand the inner surface15a. Although the location of the rolling member50′ is schematically shown inFIG. 5, actually the rolling member50′ is one, for example a column, a cylinder, a sphere, or the like, which is held at the protrusion tip35aso as to freely roll. Such the rolling member50′ contact with and rolls on the inner surface15a, thereby ensuring the smooth sliding operation of the slider30.

Variant of the Second Embodiment

In the second embodiment shown inFIG. 5, only one protrusion35is provided with the rolling member50′ at its tip. But, both of the protrusions35,36(or further additional protrusions) could be provided with the rolling member50, likewise.

In the second embodiment, the force acting in the direction of the arrow “A” onto the slider30is received by the rolling member50, and thus, the rolling member50carried by the slider30could be omitted. But, in such the case, there may be preferably provided a suitable gap, between the slider30and the outer surface of the cutter knife body11.

Third Embodiment—the Blade-Support Rolling Member is Provided

FIG. 6shows the third embodiment of the present invention, schematically. InFIG. 6, only the upper wall and the lower wall of the sleeve-like cutter knife body are shown with the hatching of cross-section. Further, for the sake of better understanding, only the blade20is drawn in somewhat perspectively.

On the upper wall, the slider30is slidably mounted, and the protrusions35,36extend downwardly from the sliding member31, which slide together with the slider30. These protrusions35,36are made engaged into the holes25,26formed on the blade20.

The above basic configuration in the third embodiment is the same as those in the first and second embodiments, which were already explained.

The third embodiment is different from the first and second embodiments in that rolling members51(blade-support rolling member) are provided between the lower surface of the blade20and the lower wall. The blade-support rolling members51are to support the blade surface far from the slider30with rolling contact on it, thereby securing the smooth sliding operation of the blade20.

As is explained above, thanks to the construction of the first or the second embodiment, the blade20is prevented from being pressed onto the bottom wall of the cutter knife by the external force acting on the slider30. But, there may be a possibility that some other unwilling external force via another route would act on the blade20. Even in such the case, thanks to the existence of the blade-support rolling member51, frictional interference between the blade20and the bottom wall of the cutter knife could be prevented, thereby securing the smooth sliding operation.

The construction shown inFIG. 6may be preferably provided additionally on the construction of the first or the second embodiment. But, even if the construction shown inFIG. 6is provided solo, the smooth sliding operation of the blade20could be secured.

As the blade-support rolling member51, a column, a cylinder, a sphere or the like suitable could be employed, as long as with which the friction can be lowered taking advantage of rolling contact. Such the blade-support rolling member51would be mounted in a suitable manner and at a suitable location. Further, the blade-support rolling members51are preferably provided in plural along with the sliding direction of the blade20, as shown inFIG. 6. But, even if only one blade-support rolling member51is provided, some extent of the same effect could be obtained.

Fourth Embodiment—the Sliding-Member-Support Rolling Member is Provided

FIGS. 7A and 7Bshow the fourth embodiment of the present invention, schematically. InFIGS. 7A and 7B, only the blade20, the slider30, the sliding member31, and the cover member45are shown, taken out ofFIG. 1. In this embodiment, the sliding member31, on which the slider30is fixed, is held in the cover member45, and thus is able to slide, being guided by the inner surface of the cover member45.

Here, in between the sliding member31and the cover member45, a plurality of rolling members52(sliding-member-support rolling member) are provided along with the longitudinal direction of the sliding member31.

The sliding member31is supported by the plurality of sliding-member-support rolling members52, which are provided along with the longitudinal direction of the sliding member31. In other words, the sliding member is supported by rolling members at discrete several points along with the longitudinal direction of the sliding member31. Therefore, even if an external force acting in the direction of the arrow “A” is applied onto the slider30which is located at the end of the sliding member31, the sliding member30would scarcely be inclined to its sliding direction (if the inclination of the sliding member31occurs, the blade20existing below the sliding member31may be pressed onto the bottom wall of the cutter knife body, and thus not preferable).

In the embodiment shown inFIGS. 7A and 7B, a plurality of the sliding-member-support rolling members52are provided between the sliding member31and the cover member45. Other than such the construction, some construction would bring the same effect, for example where an elongated sliding member31is employed, and the sliding member is guided by some surface extending along its longitudinal direction (sliding direction), and a plurality the sliding-member-support rolling members52are provided there.

As the sliding-member-support rolling member52, a column, a cylinder, a sphere or the like suitable could be employed, as long as with which the friction can be lowered taking advantage of rolling contact. Such the sliding-member-support rolling member52would be mounted in a suitable manner and at a suitable location.