JPS635320Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an opening/closing device such as a reflector cover of a projector, for example.

[Background technology and its problems]

Generally, a projector has a main body 1 as shown in Figure 1.
Light emitted from a projection tube provided in the main body is reflected by a mirror 20 attached to the main body, and the reflected light is projected onto a screen 21. In such a projector, the reflector cover 3 to which the mirror 20 is attached can be freely opened and closed with respect to the main body 1 in order to make the overall shape compact.

For example, the following types of opening/closing devices for opening and closing the reflector cover 3 of such a projector are conventionally known.

That is, as shown in FIG. 1, the reflector cover 3 is attached to the main body 1 of the projector by a hinge 2 so as to be openable and closable, and the opening and closing of the reflector cover 3 is adjusted by an arm 4 constituting an opening and closing device. One end of the arm 4 is supported by a shaft 15 on the reflector cover 3, and an intermediate portion of the arm 4 is supported on the main body 1 by a shaft 16. Main body 1
A pair of arms 4 are provided on both side walls of the
As shown in FIG. 2, a coil stand 6 is slidably housed inside a metal cylindrical body 5, and coil springs 8, 9 are disposed on both sides of this coil stand 6 having a through hole 7. The other ends of the coil springs 8 and 9 are arranged to face a stopper 10 and a sliding body 12 having a through hole 11. Further, a long hole 1 is provided in the side wall of the cylindrical body 5, facing the coil stand 6 and the sliding body 12.
3 and 14 are formed. A shaft 16 is inserted into the through hole 7 of the coil stand 6, and the shaft 16 is adapted to move within the elongated hole 13. In addition, the sliding body 12
A shaft 15 is inserted into the through hole 11 .

The reflector cover 3, which can be opened and closed by such an arm 4, is attached to the main body 1.
When the coil stand 6 is in position A shown in FIG. 1, which is completely closed, the coil stand 6 moves to the left in FIG.
The spring 9 is in a contracted state. Further, when the reflector cover 3 is fully opened and in position B, the coil stand 6 moves to the right and the spring 8 is in a contracted state.
That is, the reflector cover 3 placed at position A is always urged counterclockwise in FIG. 1 by the spring 9, and the reflector cover 3 placed at position B is urged clockwise by the spring 8. It is designed to be constantly biased in the direction. Also, C in Figure 1
The reflector cover 3 at the position is placed in balance with the weight balance point of the reflector cover 3.

Next, the force that the arm 4 receives from the reflector cover 3 will be explained based on FIG. 3.
The reflector cover 3 shown in FIG.
It is placed in a state where it is rotated about the hinge 2 at an angle θ relative to the center. Center of gravity 17 of reflector cover 3
is located at a distance a from the hinge 2, and is located at an angle α closer to the main body 1. Therefore, the center of gravity 17 is
It is placed at an angle of (θ-α) with respect to the
Further, the shaft 15 that pivotally supports the arm 4 on the reflector cover 3 is located at a distance b from the hinge 2. If the weight of the reflector cover 3 is w and the rotational direction tangential force applied to the shaft 15 is F, then the moment balance of the force in the rotational circumferential direction with the hinge 2 as the origin is given by the following equation.

aw _sio (θ-α) = bF If we calculate the force F from this, we get F=a/bw _sio (θ-α). The force F ₁ of this force F in the four directions of the arm is
If the angle between the rotation direction tangent of the shaft 15 and the arm 4 is ψ, then F ₁ =a/bwsin(θ−α)/cosψ. Here, the angle ψ is a function of the angle θ.
The force applied in the four directions of the arm obtained in this way
If F ₁ is calculated with respect to the opening/closing angle θ of the reflector cover 3, it will be as shown in I in FIG. 4. Further, the change in force due to the coil springs 8 and 9 housed in the arm 4 is linear with respect to the above angle θ,
It will look like the one in Figure 4. In addition, in Fig. 4, A,
B and C correspond to the open/close positions A, B, and C of the reflector cover 3 relative to the main body 1 shown in FIG.

As shown in FIG. 4, between the position B where the reflector cover 3 is fully opened and the position C where it is balanced at the weight balance point, the force by the coil spring 8 is a force F ₁ in the direction of the arm 4 due to the weight W of the reflector cover 3. It's getting bigger. Therefore, from the position of C to B
When the reflector cover 3, which is biased clockwise in FIG. 1 by the coil spring 8, returns to the position C, that is, the weight balance point of the reflector cover 3, when the user releases the hand when opening and closing the reflector cover 3 to the position C.

As described above, the conventional opening/closing device has the disadvantage that when the reflector cover 3 is opened/closed, the reflector cover 3 returns to the weight balance point and becomes a half-open state.

Further, the arm 4 is constructed by incorporating two coil springs 8 and 9, and has a drawback of being structurally complicated.

[Purpose of invention]

The present invention was proposed in view of the above circumstances. For example, in an opening/closing device for opening and closing the reflector cover of a projector, when the reflector cover is opened or closed, the reflector cover returns to the weight balance point and becomes a half-open state. To provide a low-cost opening/closing device with a simple structure, capable of smoothly opening/closing with a small force, and preventing sudden opening/closing operations.

[Summary of the idea]

To achieve this purpose, the opening/closing device of the present invention includes a main body, a lid attached to the main body so as to be rotatable and openable, one end of which is pivotally connected to the movable end of the lid, and the other end of the lid is pivotally connected to the movable end of the lid. a connecting rod supported so as to be movable along a guide rail provided on the body; a spring member hooked between the other end of the connecting rod and the main body; The locking and fixing position is located within a stroke range of movement of the other end of the connecting rod, and is located outside the locus of movement of the other end of the connecting rod.

〔Example〕

An embodiment in which the present invention is applied to, for example, an opening/closing device for a reflector cover of a projector will be described with reference to FIGS. 5 to 11.

As described above, the projector is configured to reflect light emitted from a projection tube provided in the projector body 30 by a mirror 31 and project the reflected light onto a screen 32. This mirror 31 is attached to a reflector cover 33, and in order to make the overall shape of the projector more compact,
The reflector cover 33 constituting the lid is attached to the main body 3.
0 with a hinge 34 as a fulcrum so that it can be rotated open and closed. One end of a connecting rod 35 is pivotally connected to the movable end of the reflector cover 33 by a shaft 36. That is, the shaft 36 is inserted into a hole 35A formed at one end of the connecting rod 35. Further, a guide rail 37 is arranged and fixed on the side surface of the main body 30. A sliding body 39 having, for example, a bearing 38 is attached to this guide rail 37, and a sliding plate 40 is attached to the guide rail 37 so that it can freely slide in the longitudinal direction of the rail 37 via this sliding body 39. It is ready to be installed. A pin 41 is planted and fixed on this slide plate 40, and the other end of the connecting rod 35 is connected to this pin 4.
It is designed to be pivoted on 1. Therefore,
The other end of the connecting rod 35 is supported by the guide rail 37 so as to be movable along the guide rail 37. Further, a pin 42 is planted and fixed on the slide plate 40.
A groove 43 is formed over the entire circumference in the radial direction. Further, a protrusion 44 is provided on the side surface of the main body 30, and a coil spring 45, which is a spring member, is hooked onto the groove 43 of the pin 42 and the protrusion 44. Therefore, one end of the coil spring 45 is movable along the guide rail 37 similarly to the other end of the connecting rod 35 described above. Note that the pins 41 and 42 may be replaced with one pin, and one end of the connecting rod 35 and one end of the coil spring 45 may be attached to the pin. The position where the other end of the coil spring 45 is latched and fixed to the main body, that is, the position where the protrusion 44 is formed on the side surface is within the movement stroke range of the other end of the connecting rod 35, and It is arranged at a position away from the movement locus of the other end. FIG. 6 shows that the reflector cover 33 rotates around the hinge 34 and the connecting rod 3
The other end of the reflector cover 33 is moved along the guide rail 37, and the reflector cover 33 is placed at the position C in the figure, where the weight of the reflector cover 33 is balanced at its weight balance point. At this time, directly below the pin 42 on the slide plate 40 that is stationary on the guide rail 37,
In this embodiment, the protrusion 44 is formed,
At this time, the coil spring 45 hooked to the pin 42 and the projection 44 is placed in a free length state. Note that the protrusion 44 may be provided directly above the pin 42 instead of directly below it.

FIG. 5 shows a state in which the reflector cover 33 is placed at position B in the figure, where it is fully opened with respect to the main body 30. When the reflector cover 33 is closed from this state, the spring force of the coil spring 45 acts in the direction of the arrow in FIG. 5 to reduce the closing force. When the reflector cover 33 reaches the weight balance point shown in FIG. 6, the coil spring 45 has a free length and no spring force acts. Further, when the reflector cover 33 is closed, the spring force acts in the opposite direction, so that it does not close suddenly.

The reflector cover 33 shown in FIG.
It is placed at position A in the figure, where it is completely closed to the outside. When the reflector cover 33 is opened from this state, the spring force of the coil spring 45 acts in the direction of the arrow in FIG. 7, so that the reflector cover can be opened with a weak force. Moreover, when the reflector cover 33 is opened further beyond the weight balance point, the spring force acts in the opposite direction, so that the reflector cover 33 is prevented from opening suddenly.

Next, the connecting rod 35 is connected to the reflector cover 33.
An explanation of the force exerted by this will be given with reference to FIG. 9th
The reflector cover 33 shown in the figure is in a state of being rotated about the angle hinge 34 of θ with respect to the main body 30. Moreover, the center of gravity 46 of the reflector cover 33 is
It is located at a distance a from the hinge 34 and has an angle of α
Since it is close to 0, it is at an angle of (θ-α) with respect to the main body. Further, the shaft 36 which pivotally supports one end of the connecting rod 35 on the reflector cover 33 is connected to the hinge 3
It is at a distance b from 4. If the weight of the reflector cover 33 is W and the rotational direction tangential force applied to the shaft 36 is F, then the moment balance of the force in the rotational circumferential direction with the hinge 34 as the origin is aw _sio (θ−α) = bF. Given. If we calculate the force F from this, we get F=a/bw _sio (θ−α). The component of this force F in the direction of connecting rod 35
F ₁ becomes F ₁ =a/bw _sio (θ−α)·1/cos ψ, where ψ is the angle between the rotational direction tangent of the shaft 36 and the connecting rod 35. Furthermore, if the angle between the extension line of the connecting rod 35 and the longitudinal direction of the guide rail 37 is φ, then the force F ₁
The component F ₂ of the force acting in the longitudinal direction of the rail 37 is F ₂ =a/bw _sio (θ−α)·cosφ/cosφ. Further, the force component F ₃ of the force F ₁ in the direction perpendicular to the guide rail 37 is F ₃ =a/bw _sio (θ−α)·sinφ/cosψ. This force _F3 is a force that acts as a frictional force when the slide plate 40 slides on the guide rail 37. Therefore, if the coefficient of friction is μ, when the reflector cover 33 rotates around the hinge 34, the weight of the cover 33 is
The force f actually applied in the longitudinal direction of 7 is f=F ₂ +μF ₃ . In this example, the friction coefficient μ is 0.2,
Also, since the angles ψ and φ are functions of θ, the change in the force f is expressed as the opening/closing angle θ of the reflector cover 33.
When calculated, it becomes as shown in Fig. 10.

Also, when the reflector cover 33 is in the above-mentioned positions A, B, and C with respect to the main body 30, the positions of one end of the coil spring 45, which is locked to the pin 42 on the slide plate 40, on the guide rail 37 are respectively shown. A′, B′, and C′, the spring force of the coil spring 45 acting in the longitudinal direction of the rail 37 is the 11th
It can be represented schematically by the figure.

In FIG. 11, the distance between point B' and the projection 44, that is, the spring length of the coil spring 45 when the reflector cover 33 is fully opened with respect to the main body 30, is l ₁ , and the distance between point A' and the projection 44 is l1. The spacing is l ₂ .
Further, the free length of the coil spring 44 is γ. In addition, the angle between the coil spring 44 and the guide rail 37 when one end of the coil spring 44 is at point B' is M, and the spring force of the coil spring 44 at this time is
7, the force F _B is F _B =(l ₁ −γ)k· _{cps M} . Here, k is a spring constant. Also,
The angle between the coil spring 44 and the guide rail 37 when one end of the coil spring 44 is at point A' is N,
If the component force of the spring force of the coil spring 44 in the longitudinal direction of the rail 37 at this time is F _A , then the force F _A is F _A =(l ₂ -γ)k· _cps N . In this way, the forces F _B and F _A vary in a cosine manner as the angle M or N, which is a function of the angle θ, changes. When the changes in the forces F _B and F _A are calculated with respect to the change in the opening/closing angle θ of the reflector cover 33, the result is as shown in FIG. 10. In FIG. 10, A, B, and C represent the reflector cover 3.
This corresponds to the opening/closing positions A, B, and C with respect to the main body 30 of No. 3.

As is clear from FIG. 10, the force f (curve) exerted by the weight of the reflector cover 33 in the longitudinal direction of the guide rail 37 is
The spring force applied in the longitudinal direction of the guide rail 37 is always larger than the forces F _B and F _A (curves) except for the positions A, B, and C mentioned above.

Therefore, the reflector cover 33 is attached to the main body 30.
Even if you release your hand from the reflector cover 33 during the opening/closing operation when the reflector cover 33 is between the positions B and C above, the cover 33 will not move.
The cover 33 never returns to the weight balance point position (position C above) of No. 3, but always returns to the position where the cover 33 is fully open (position B above). Also,
The reflector cover 33 is placed in a position where the reflector cover 33 is between the above-mentioned positions A and C.
Similarly, even when the hand is released, the cover 33 does not return to the weight balance point position (position C above), but always returns to the fully closed position of the cover 33 (position A above). It's summery.

Therefore, according to the present invention, the drawback of conventional opening/closing devices in which when the reflector cover is removed from the reflector cover during the opening/closing operation, the cover returns to the weight balance point and becomes half-open is eliminated. There is.

Further, according to the present invention, the reflector cover 33 can be opened and closed with a weak force due to the effect of the coil spring 45, and the cover 33 does not suddenly open or close when it is completely opened or closed. There's nothing wrong with that. Furthermore, since the change in force exerted on the connecting rod 35 by the spring force of the coil spring 45 is cosine-like, it approximates the change in force when opening and closing the reflector cover 33, making the opening and closing feel very smooth. ing.

Furthermore, unlike conventional switchgear, this invention
Since it is constituted by one coil spring 45, the opening/closing operation of the reflector cover 33 is continuous, and the structure is simple, which is advantageous in terms of cost.

Although a pair of opening/closing devices of the present invention are generally provided on both sides of the main body 30 of the projector,
It may be provided only on one side. Further, the present invention may be applied to opening/closing devices of various devices other than projectors.

[Effect of idea]

As is clear from the above description, according to the present invention, one end of the connecting rod is attached to the movable end of the lid body, and the other end of the connecting rod is slid on the guide rail provided on the main body. The body is opened and closed relative to the main body, and this opening and closing is controlled by a single coil spring. Therefore, the lid body does not return to the weight balance point when opening and closing, and no large force is required when opening and closing, and sudden opening and closing does not occur. Furthermore, since one coil spring is used, opening and closing operations can be performed continuously. Furthermore, the structure is simple and the present invention can be realized at low cost.

[Brief explanation of the drawing]

Fig. 1 is a side view of the projector showing a conventional switchgear used in the projector, Fig. 2 is a front view of the components of the conventional switchgear, and Fig. 3 is the force applied during opening and closing of the conventional switchgear. A schematic diagram showing the relationship between
Fig. 4 is a diagram showing the characteristics of the force due to the weight of the reflector cover and the force due to the coil spring in a conventional opening/closing device, and Figs. 5 to 7 are diagrams showing the characteristics of the force due to the weight of the reflector cover and the force due to the coil spring in a conventional opening/closing device. 8 is an external perspective view showing the components of the opening/closing device according to the present invention, FIG. 9 is a schematic diagram showing the force relationship when opening/closing the opening/closing device according to the present invention, and FIG. The figure is a diagram showing the characteristics of the force due to the weight of the reflector cover and the force due to the coil spring in the switchgear according to the present invention, and FIG. 11 is a schematic diagram showing the spring force of the coil spring in the guide rail direction of the switchgear according to the present invention. . 30...Projector body, 31...Mirror,
32...Screen, 33...Reflector cover, 34...Hinge, 35...Connecting rod, 36...
Shaft, 37...Guide rail, 40...Slide plate, 41, 42...Pin, 44...Protrusion, 45...
...Coil spring, 46...Center of gravity of reflector cover.

Claims (1)

[Scope of utility model registration request] A main body, a lid attached to the main body so as to be rotatable and openable, one end of which is pivotally connected to the movable end of the lid, and the other end is movable along a guide rail provided on the main body. It has a supported connecting rod, and a spring member hooked between the other end of the connecting rod and the main body, and the locking and fixing position of the spring member to the main body is determined by the movement stroke of the other end of the connecting rod. An opening/closing device characterized in that the opening/closing device is provided at a position within the range and away from the movement locus of the other end of the connecting rod.