JPS6140860B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a motion conversion mechanism that converts reciprocating motion into unidirectional rotational motion.

The piston crank mechanism is the most commonly used mechanism for converting reciprocating motion into rotational motion. In the piston crank mechanism, one reciprocation corresponds to one revolution, and the rotational angular velocity of the output shaft changes depending on the phase of the reciprocating motion. Piston crank The mechanism cannot be used. In such cases, a motion conversion mechanism consisting of a rack and pinion was used, but not only is the rack and pinion itself quite expensive, but it is also difficult to obtain rotational output from reciprocating motion in one direction. In this case, two pinions are required, and each pinion must be attached to the output shaft via a one-way clutch, which increases the cost of the device.

The purpose of this invention is to obtain an inexpensive mechanism for converting reciprocating motion into unidirectional rotational motion having an angular velocity proportional to the velocity of the motion.
The above-mentioned motion conversion is performed using only a pulley, two cables, and two springs.

Hereinafter, this invention will be explained in detail based on the drawings.

A machine frame 3 is slidably attached to the rails 1 of a machine frame 2 having two rails 1 so as to be able to reciprocate along these rails. An output shaft 4 is pivotally attached to the machine base 3, and a pulley 6 having two grooves 5a and 5b is fixed to the output shaft 4. Two cables 7a, 7b are stretched on the machine frame 2 in parallel with the rail 1, and these cables 7a, 7b are attached to the pulley 6 from opposite sides of the pulley 6. Grooves 5a, 5b
are wrapped around each. Also, this cable 7a,
7b has springs 8a and 8b only at one end thereof, respectively.
is interposed, and one spring 8a is attached to one side 2a of the machine frame 2.
The other spring 8b is fixed to the other side 2b of the machine frame 2, and tension is applied to the cables 7a, 7b by the spring force of the springs 8a, 8b. As will be described later, depending on the position of the springs 8a and 8b, the output shaft 4
The direction of rotation of the springs 8a, 8a and 8a are determined, as shown in the figure.
8b is interposed, the output shaft 4 rotates counterclockwise in FIG. When positioned on the right side of the figure, the output shaft 4 rotates clockwise in the figure. Also, these springs 8a, 8b
The spring force, together with the friction coefficient between the pulley 6 and the cables 7a and 7b, is a factor that determines the torque output from the output shaft 4. If you want to obtain a large output torque, use a spring with a large spring force. It is necessary to use it. If the spring forces of the springs 8a and 8b are different, the output torque will vary depending on the sliding direction of the machine base 3, so it is necessary to use the same springs 8a and 8b, resulting in assembly errors. If there is a risk, it is preferable to interpose fine adjustment screws between the springs 8a, 8b and the machine frame 2 so that the spring force can be adjusted.

The operation of the motion conversion mechanism constructed as described above will be explained with reference to FIG. 4, which schematically shows this mechanism. In FIG. 4, the tension in the part of the cable 7a on the right side of the pulley 6 is T ₁ , the tension in the part on the left side is T ₂ , and the tension in the part of the cable 7b on the right side of the pulley 6 is T ₃ , on the left side Let T ₄ be the tension at the part. When the pulley 6 moves to the right along the cables 7a and 7b, the pulley 6 and the cables 7a and 7b wound around it
The frictional force with increases the tensions T ₂ and T ₄ and the tension T ₁
and T ₃ , and the tensions T ₁ and T ₄ have a spring 8 on the line of action.
Since a and 8b are interposed, the tension T ₁
And T ₄ is held at a value equal to this spring force and does not change, and only tension T ₂ increases and only tension T ₃ decreases. Therefore, while the cable 7a is tightly tied to the pulley 6 and attempts to rotate the pulley 6, the cable 7b is loosened and the cable 7b and the pulley 6 slide, and the pulley 6 is attached to the cable 7a. It rolls along. That is, the pulley 6 rotates counterclockwise when viewed from arrow B in FIG.

When the pulley 6 moves to the left, the tension T ₃ increases and the tension T ₂ decreases for the same reason.
The cable 7b is tightened and the cable 7a is loosened. Therefore, the pulley 6 rolls along the cable 7b, and the pulley 6 rotates counterclockwise when viewed from the arrow B, similar to when the pulley 6 moves to the right.

When the spring 8a is installed on the left side of the pulley 6 and the spring 8b is installed on the right side of the pulley 6, changes in tension will occur in the tensions T ₁ and T ₄ .
When the pulley 6 moves to the right, the pulley 6 is tightened by the cable 7b, and when the pulley 6 moves to the left, the pulley 6 is tied by the cable 7a. A clockwise rotation occurs when viewed from.

Such a change in the tension of the cables 7a, 7b is caused by the relative reciprocating motion between the pulley 6 and the cables 7a, 7b, so if the machine frame 2 is fixed and the machine frame 1 is moved reciprocatingly, Even when the machine frame 1 is fixed and the machine frame 2 is reciprocated, a rotational output in one direction is always obtained from the output shaft 4.

As mentioned above, the motion conversion mechanism of the present invention converts reciprocating motion into unidirectional rotational motion using only a pulley, two cables, and two springs, so it can be manufactured at an extremely low cost. In addition, no matter how large the input stroke of reciprocating motion is, it can be easily adapted to the input reciprocating stroke, and even an extremely small device can be easily manufactured. It is extremely effective as a motion conversion mechanism used when it is desired to apply rotational force to a device installed above by utilizing its reciprocating motion.

[Brief explanation of the drawing]

1 to 3 show an embodiment of the present invention, in which FIG. 1 is a plan view, FIG. 2 is a side view, and FIG. 3 is a view taken along the A-A plane in FIG. This is a cross-sectional view, and FIG. 4 is a perspective view schematically showing this mechanism. 1...Rail, 2...Machine frame, 3...Machine base, 4...
Output shaft, 6...Pulley, 7a, 7b...Cable, 8
a, 8b... spring.

Claims (1)

[Claims] 1. A machine frame and a machine stand are linked together so that they can move relatively back and forth along a rail provided on either of them, a pulley is pivoted to the machine frame, and two cables are attached to the machine frame parallel to the rails. A spring is interposed only at one end of each of these two cables, one of the springs is positioned on one side of the machine frame, and the other is located on the other side of the machine frame, and this cable A motion conversion mechanism characterized in that the strips are wound around the pulley from opposite sides.