JPH034838Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to a rotation transmission mechanism for concentrically connecting a drive shaft and a driven shaft to transmit rotation of the drive shaft to the driven shaft.

Prior Art Various rotation transmission mechanisms have already been proposed, such as clutch mechanisms, that concentrically connect a drive shaft and a driven shaft to transmit the rotation of the drive shaft to the driven shaft. However, a rotation transmission mechanism that compensates for the difference in load so that the load is approximately the same in both the forward and reverse rotation directions has not yet been proposed. For example, the present applicant previously reported that in a dental treatment chair, when the backrest is raised and lowered, the fulcrum between the patient's upper body and the chair itself is misaligned, resulting in a misalignment between the patient and the chair. In order to adjust the inconsistency, the chair is designed so that when the backrest is raised, the backrest is moved backward at the same time as the backrest is activated, and when the backrest is collapsed, the backrest is moved forward at the same time as the backrest is collapsed. (Refer to Utility Application No. 111572, 1983). Therefore, in the above-mentioned treatment chair, the load is different when the backrest is raised and when it is folded down (it is large when the backrest is raised because it is raised against the load, and it is small when it is folded down because it receives the load).
Therefore, if the source power is constant, the adjustment speed will be different when raising and lowering, or even if adjusted to a specified position, the position may shift excessively when folding down due to the weight of the backrest. There was a problem.

Purpose The present invention was made to solve the above-mentioned problems, and in particular, in a rotation transmission mechanism that connects a driven shaft and a drive shaft, where a rotational load is constantly applied in one direction. By adding a friction mechanism, the rotation transmission mechanism has a frictional resistance commensurate with the rotational load when stopped, thereby preventing positional shift when stopped, and rotating against the rotational load when rotating. When rotating according to the rotational load, the frictional resistance is released and the rotation is performed, and when the rotational load is applied, the frictional resistance is applied and the rotation is performed.
In other words, the load can be adjusted at the same adjustment speed regardless of the direction of rotation as the load is approximately the same.

Embodiment FIG. 1 is a side sectional view for explaining an embodiment of the rotation transmission mechanism according to the present invention, FIG. 4 is a perspective view of the main parts thereof, and FIGS. X-X
2 is a state diagram when stopped and rotating in the direction of a rotating load, and FIG. 3 is a state diagram when rotating against a rotating load. In the figure, 1 indicates the motor; 2 is the drive shaft (motor shaft), 3 is the rotor, 3
a, 3b are guide grooves provided in the rotor 3;
a and 4b are brake receivers, and 4a' and 4b' are the brake receivers 4.
The protrusions are provided on the guide grooves 3a and 4b, respectively, and each protrusion engages with the guide grooves 3a and 3b, respectively. 5
a and 5b are friction plates integrally attached to the brake receivers 4a and 4b, respectively; 6a and 6b are screws; and 7
8 is a spring; 8 is a cylindrical fixed housing disposed to surround the friction plates 5a and 5b; 9 is a cylindrical fixed housing;
10 is a bearing, 10 is a tightening nut, and 11 is a driven shaft. For example, when this invention is applied to the dental treatment chair of Utility Model Application No. 57-111572, the driven shaft 11 is a rod screw. By the rotation of the rod screw 11, the backrest is raised and lowered and moved back and forth as described above. Therefore, the present invention is a rotation transmission mechanism for concentrically connecting a drive shaft 2 and a driven shaft 11 and transmitting the rotation of the drive shaft 2 to the driven shaft 11, the rotation transmission mechanism comprising: , fixed to the driven shaft 11 and the driven shaft 1
a pair of pin members 6a extending and fixed in the axial direction of the driven shaft at symmetrical positions with respect to the radial direction of the driven shaft;
6b, and a pair of brake receiving members 4a, 4b rotatably mounted on the respective pin members 6a, 6b.
The brake receiving members 4a, 4b are arranged between the pair of brake receiving members 4a, 4b, and the driven shaft 11 is arranged around the respective pin members 6a, 6b.
a rotor 3 fixed to the drive shaft 2 and having a portion extending in the radial direction of the drive shaft 2; Guide grooves 3a, 3 extending in a direction perpendicular to the drive shaft 2 at symmetrical positions
b, and protruding members 4a', 4b' which are respectively erected on the pair of brake receiving members 4a, 4b on the side opposite to the pin members 6a, 6b, and whose tips engage with the guide grooves 3a, 3b. , a friction plate 5a attached to each of the brake receiving members 6a and 6b,
5b, and a cylindrical fixed housing 8 disposed to surround the friction plates 5a, 5b. When the drive shaft 2 rotates in one direction, the friction plates 5a, 5b and the fixed housing 8 are arranged to surround the friction plates 5a, 5b. When the inner wall of 8 comes into contact and provides rotational resistance and rotates in the opposite direction,
This is characterized in that the friction plates 5a, 5b and the inner wall of the fixed housing 8 are spaced apart from each other.
Further, to explain in detail, screws 6a and 6b are installed on the driven shaft 11 symmetrically with respect to the rotation axis of the driven shaft,
Brake receivers 4a and 4 are attached to the screws 6a and 6b, respectively.
b are arranged to be rotatable about the screws 6a, 6b as fulcrums, and furthermore, these brake receivers 4a, 4b are biased in the radial direction of the rotating shaft by a spring 7, and the friction plates 5a, 5b are deflected by a spring 7. is configured to come into contact with the inner wall of the housing 8. Therefore, when the motor is stopped, the friction plates 5a and 5b are in frictional contact with the inner wall of the housing 8, and rotation of the drive shaft and driven shaft in the direction of arrow A shown in FIG. 2 is prevented.
When rotating in the direction of arrow A (when the backrest is folded down),
Since the friction receivers 4a and 4b rotate in the directions of arrows a and a' about the screws 6a and 6b, respectively, the friction plates 5a and 5b attached to the friction receivers move outward,
It rotates while contacting the inner wall of the housing 8. Therefore, frictional resistance due to this contact is added to the motor, resulting in an increase in load to compensate for the decrease in load at the time of collapse. When rotating in the direction B shown in FIG. 3 (when the backrest starts), the friction plates 5a and 5b rotate in the directions of arrows b and b' as the fulcrums of the screws 6a and 6bb, respectively. There is no contact with the inner wall of the shaft, and rotation is transmitted without adding any frictional resistance.

Effects As is clear from the above explanation, according to the present invention, when rotating power is transmitted to a driven shaft that is always subject to a rotational load in one direction, the rotational load on the driven shaft is reduced when stopped. It is not transmitted to the drive shaft side,
Further, when rotating in the same direction as the rotational direction due to the rotational load, the rotation of the drive shaft is transmitted to the driven shaft with the rotational load added,
When rotating in the direction opposite to the rotational load, the rotation is transmitted without adding any load, so
The load state is approximately the same in any direction of rotation, and therefore, the stop position can be maintained at a constant position, and there are advantages such as easy adjustment of the stop position.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view for explaining one embodiment of the rotation transmission mechanism according to the present invention, and FIGS. 2 and 3 are operating state diagrams as viewed from the direction of the X-X line in FIG. 1. , FIG. 4 is a perspective view of the main part of FIG. 1. 1...Motor, 2...Drive shaft, 3...Rotor,
3a, 3b...Guide groove, 4a, 4b...Friction receiver, 4a', 4b'...Protrusion, 5a, 5b...Friction plate, 6a, 6b...Screw, 7...Spring, 8
... Housing, 9 ... Bearing, 10 ... Tightening nut, 11 ... Driven shaft.

Claims (1)

[Scope of utility model registration request] A rotation transmission mechanism for concentrically connecting a drive shaft and a driven shaft and transmitting rotation of the drive shaft to the driven shaft, the rotation transmission mechanism being fixed to the driven shaft and having a radius of the driven shaft. a pair of pin members extending and fixed in the axial direction of the driven shaft at symmetrical positions with respect to the direction; a pair of brake receiving members rotatably attached to the respective pin members; a spring member disposed between the brake receiving members and biasing the brake receiving members in a direction away from the driven shaft around the respective pin members; and a spring member fixed to the drive shaft and directed in the radial direction of the drive shaft. a rotor having an extending portion; a guide groove provided in the rotor and extending in a direction perpendicular to the drive shaft at a symmetrical position with respect to the drive shaft; and a guide groove provided in the rotor and extending in a direction perpendicular to the drive shaft; a protrusion member that is erected on the opposite side of the member and whose tip engages with the guide groove; a friction plate that is attached to each of the brake receiving members; and a friction plate that is arranged to surround the friction plate. When the drive shaft rotates in one direction, the friction plate and the inner wall of the fixed housing come into contact to provide rotational resistance, and when the drive shaft rotates in the opposite direction, the friction plate A rotation transmission mechanism characterized in that a plate and an inner wall of a fixed housing are separated from each other.