1. Field of the Invention
The present invention relates to a compass provided with a ratchet mechanism. In particular, the present invention also relates to, not only a compass for drawing a circle, but also a compass-cutter for cutting a cloth in circular configuration, the compass-cutter being provided with a ratchet mechanism.
2. Description of the Related Art
When a user draws a circle, the user pinches the manipulate portion 19 with fingers, and moves the pencil 16 along a circular path, with the needle 12 stuck on a drawing paper being the center of the circular path. During this operation, it may be difficult to draw a complete 360 degree circle in a single action without re-pinching the manipulate portion with the fingers. Therefore, the user often re-pinches the manipulate portion before completing a circle, and thereafter finishes the circle. This action of re-pinch is cumbersome, and if this re-pinch action is poor, the user can not draw a precise circle, because of unintentional shift of the needle 12, for example.
On the other hand, if the user forcibly tries to draw up a complete circle in a single action, an excessive force may shift the needle 12 relative to the drawing paper, and as a result, a precise circle could not be drawn.
The above disadvantages also are applicable to a compass-cutter for cutting an object in circular configuration.
Therefore, an object of the present invention is to provide a compass and a compass-cutter, which can be smoothly manipulated with simple manipulating actions.
The present invention was completed in order to effectively solve the foregoing problems, and provide a compass and a compass-cutter as described below.
The feature of the present invention lies in that a manipulate portion of a compass comprises a ratchet mechanism. This feature can be applied not only to a compass for drawing a circle, but also to a compass-cutter for cutting an object in circular configuration. Note that an expression “drawing a circle” covers not only the fact to draw a circle with a pencil carried on one leg of a compass, but also the fact to draw a circle with a needle on metal surface.
Generally, the manipulate portion is intended for manipulation with fingers. But, when the compass is large sized, or when the object to be cut is hard, it may be preferable to manipulate the compass with a tool. In such the case, it is preferable that at least a part of the manipulate portion has a configuration adopted to be engaged with a tool.
Further, the manipulate portion comprising the ratchet mechanism can be constituted as a separable component from a body of the compass. In such the case, a commercially available tool (for example, a ratchet handle for socket wrench, and so on) can be used as the manipulate portion comprising the ratchet mechanism.
This and other objects and features of the present invention will become apparent from the following description taken in conjunction with the preferred embodiments thereof with reference to the accompanying drawings.
The embodiments of the present invention will be described in detail below, with reference to the accompanying drawings.
The compass-cutter 20 is used for cutting a paper or a cloth in a circular configuration. In use, a user sticks the needle 61 at the center of a circle, and pinches a manipulate portion 30 with fingers and rotates the manipulate portion so as to move a blade 81 along a circular path. The manipulate portion 30 is provided with a ratchet mechanism (one-way clutch) therein.
The ratchet mechanism transmits a rotational driving force only in one direction. As to specific constructions of the ratchet mechanism, a variety of ratchet mechanisms are known, and therefore, in the present invention, the specific construction of the ratchet mechanism is not limited to particular construction.
(Construction of a Ratchet Mechanism)
At the upper side of a compass body 50, the first cylindrical member 34 is fixed, so that the compass body 50 and the first cylindrical member 34 can not be rotated relative to one another. The first cylindrical member 34 is provided with teeth at its upper end.
In
The member 33 is connected to the body 31 of the manipulate portion, at its square column 33a, and therefore, the member 33 must rotate with the body 31 of the manipulate portion. The member 33 can slide axially within the body 31 of the manipulate portion.
Note that, if a relatively heavy member is employed as the member 33, the spring 32 can be omitted. In
(Function of Ratchet Mechanism)
When the manipulate portion 30 is rotated in the direction of “A” in
Therefore, after first pinching the manipulate portion 30 with fingers to rotate the manipulate portion 30 in the direction of “A”, so as to cut a paper (or cloth) with the blade 81, when the cutting operation proceeds to some extent, the manipulate portion 30 is rotated in the direction of “B” while the blade 81 remains stationary, and then the manipulate portion 30 is again rotated in the direction of “A”, to proceed the cutting. Repeating the above procedures, the user can smoothly rotate the blade a full 360 degrees with simple hand actions, without excessive force or disruptive finger repositioning, as there is no need for re-pinching the manipulate portion 30 during the cutting operation.
(Other Mechanism of the Compass-Cutter 20)
The remarkable construction and function of the compass-cutter 20 according to the present invention are described as above, and the other matters are generally well known. Thus, the summarized explanations are made below.
The blade 81 is mounted at one end of a horizontal bar 70 via a mount plate 80. A screw member 82 is intended for exchanging the blade 81 with another blade. The horizontal bar 70 is carried on the compass body 50 so as to slide in horizontal direction. The interval between the needle 61 and the blade 81 (namely, the radius of circle) can be adjusted with a bolt 52 and screw member 51. The horizontal bar 70 bears a scale 71 for indicating the interval.
The needle 61 is located co-axially with the manipulate portion 30, and is fix to lower side of the compass body 50 via a shaft member 60.
(A Modification of the Manipulate Portion)
In
The hexagonal head 31a of the body 31 is to be engaged with a spanner 100. That is, the compass-cutter in
In the shown modification, the head 31a is made hexagonal so as to be engaged with the spanner 100. The configuration of the head does not need to be hexagonal. Any suitable configurations (for example, rectangular) can be employed as long as the configurations match with a tool to be used (spanner, monkey wrench, wrench, and so on). Further, the configuration can be provided at other location than the head of the body 31. For example, the circumferential wall of the body 31 can be partially cut out, so as to be engaged with a tool.
(An Embodiment Wherein the Compass Body and the Ratchet Mechanism are Separated)
In
In the compass-cutter 120, the cylindrical member 151 fixed at upper side of the compass body 150 is not provided with a ratchet mechanism, and alternatively, a square recess 152 is formed at the center of the cylindrical member 151. A ratchet mechanism is enclosed in the end portion 131 of the manipulate portion 130. From the end portion 131, a square protrusion extends downwardly to be engaged in the square recess 152, though the protrusion does not appear in FIG. 6. With the protrusion (not shown) being engaged in the square recess 152, a user manipulates the handle 132 to cut an object in circular configuration.
In the compass-cutter 120 shown in
(Other Embodiments)
Both of the compass-cutter 220 in FIG. 7 and the compass 320 in
(Another Ratchet Mechanism)
Next, with reference to
The outer sheath 600 carries a plurality of circular columns on its inner surface by means of a holding mechanism (not shown). Although only three columns 501, 502, and 503 are shown in
As partially enlarged in
When the outer sheath 600 is rotated in the same direction (the arrow “A”) as the direction to which the biasing force of the spring is applied, the rotational torque applied to the outer sheath 600 is not transmitted to the center shaft 500, and therefore, the outer sheath 600 rotates without transmitting rotaty motion to the center shaft 500. Each of the circular columns 501, 502, 503 follows the gentle first slope 601a, 602a, 603a under the biasing force of the spring.
When the outer sheath 600 is rotated in the oppposite direction (the direction denoted by arrow “B”), each of the circular columns 501, 502, 503 is pressed against the gentle first slope 601a, 602a, 603a under the biasing force of the spring. As a result, since the diameter of individual circular column is set larger than the gap between the center shaft 500 and the outer sheath 600, each of the circular columns 501, 502, 503 engages the wedged-space between the gentle first slope and the outer surface of the center shaft 500, so that the rotational torque applied to the outer sheath 600 is transmitted, via the circular columns, to the center shaft 500, and therefore, the compass rotates.
(A Compass-Cutter Wherein the Manipulate Portion can be Always Located at Intermediate Position Between the Rotation Center and the Blade)
However, in the embodiment in
In the compass-cutter in
Such the construction is particularly advantageous in a compass-cutter wherein a blade is utilized for cutting an object in circular configuration. This is explained below.
When a blade is set to one leg of a compass as shown in
To the contrary, in the construction in
Using the ratchet mechanisms explained above with the compass-cutter constructed as shown in
(Manipulate Portion in
A rod 981 is stationary fixed to the compass-body 950. A threaded end portion 982 of the rod 981 passes through an opening 991 formed on an upper wall of a sheath 990, and a nut 983 is engaged with the threaded end portion 982. As a result, the sheath 990 is attached to the rod 981 so as to freely rotate in both directions.
When such the manipulate portion is employed, the cutting operation with the rotary blade 801 is to be conducted by revolving use's hand holding the sheath 990 around the needle 701. This construction provides additional benefits. For example, the cutting operation can be conducted in both left and right directions, and therefore the cutting operation can be easily conducted regardless of a left-handed user or a right-handed user. Further, the manipulate portion can be simplified as compared to an embodiment employing a ratchet mechanism.
Note that in the case of the manipulate portion in
(Manipulate Portion in
The manipulate portion comprises one rod 955, which is stationary fixed to the compass body 950. This construction is inferior to the construction in
In the compass-cutters in
(Mechanism for Positioning the Manipulate Portion at Intermediate Position Between the Rotation Center and the Blade)
In
In the compass-cutter in
Two springs 965 and 966 have the equal spring-rate. Thus, tightening the screw member 751 to fix the position of the slide member 750, while loosening the screw member 951 to allow the compass body 950 to slide freely, allows the manipulate portion 960 to be automatically located at the intermediate position between the rotation center (the position of the needle 701) and the blade 801, under the opposing forces of the spring 965, 966. Once centered, the screw member 951 may be tightened to fix the position of the compass body 950.
In the embodiment in
In the compass-cutter in
The mount plate 800 carrying the blade 801 is fixed to a slide member 800a, and engaged with the left screw 972 via the slide member 800a. That is, the slide member 800a is provided with a threaded portion (not shown) therein, and this threaded portion is engaged with the left screw 972. On the other hand, the slide member 750a carrying the needle 701 is provided with a threaded portion (not shown) therein, and this threaded portion is engaged with the right screw 973.
Since the left screw 972 and the right screw 973 are oppositely threaded, rotating the dial portion 971, exposed on the side wall of the compass body 950a, causes the blade 801 and the needle 701 to move toward or away from each other, while the manipulate portion 950 remains at an intermediate position therebetween.
Thus, in the compass-cutters in
Although the present invention has been described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications are apparent to those skilled in the art. Such changes and modifications are to be understood as included within the scope of the present invention as defined by the appended claims unless they depart therefrom.
Number | Date | Country | Kind |
---|---|---|---|
2001-291444 | Sep 2001 | JP | national |
2002-103759 | Apr 2002 | JP | national |
2002-187806 | Jun 2002 | JP | national |
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Number | Date | Country | |
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20030056378 A1 | Mar 2003 | US |