JP2001124051A - Free stop device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a free stop device capable of certainly preventing a leaf spring from slipping out and establishing uniform braking characteristics while increase of the manufacturing costs is well suppressed. SOLUTION: The free stop device has a leaf spring 3 bent so that the cross- section assumes an approximately U-form, which pinches a shaft 1 between a pair of mutually opposing leg plates 21 and gives a braking force to the shaft by engaging the leg plates with a bracket 2 pivoted on the shaft, wherein the contacting part 21a of each leg plate with the shaft is formed flat, while the part nearer the forefront 21b than the contacting part 21a is furnished with a slipoff preventive part 26 to be engaged with the shaft or bracket for restricting the slipping-out from the bracket.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a free-stop device for stopping and holding a member at an arbitrary position, and more particularly, to a required braking force by a leaf spring which is bent so as to have a substantially U-shaped cross section and sandwiches a shaft between a pair of leg plate portions facing each other. And a free stop device for obtaining

[0002]

2. Description of the Related Art In a multi-stage paper feed tray of an OA device having a printing mechanism such as a copying machine, an upper paper feed tray is tilted upward to accommodate sheets in a lower paper feed tray. There is something. In such a paper feed tray, a free stop device is provided in a hinge portion so that the free stop device is held at an arbitrary angle when tilted. 2. Description of the Related Art There is a known type in which a required braking force is obtained by a leaf spring which is bent in a letter shape and sandwiches a shaft between a pair of leg plate portions facing each other.

[0003]

In such a free stop device, the shaft and the bracket pivotally connected to the shaft are respectively connected to the support member on the main body side and the paper feed tray so as to be relatively non-rotatable. Is locked to the bracket to regulate the relative rotation of the leaf spring with respect to the bracket, so that the braking force of the leaf spring on the shaft acts as a rotation resistance between the sheet feeding tray and the support member. Then, since the force in the direction of detaching from the bracket acts on the leaf spring due to the relative rotation of the shaft, it is necessary to restrain the leaf spring on the bracket against this detaching force, and in this case, the manufacturing cost increases significantly. It is desired to have a structure capable of reliably preventing the leaf spring from being detached even if it is not performed.

[0004] In order to meet this demand, by forming both sides of the contact portion with the shaft narrower than the diameter of the shaft, the displacement of the leaf spring with respect to the shaft is suppressed and the detachment from the bracket is prevented. can do. However, in this configuration, since the contact portion with the shaft, which requires high precision for smooth operation, has a bent cross-sectional shape, the production cost increases when trying to secure the required braking force with high precision. Occurs. In particular, when the shaft has a substantially D-shaped cross-section in which a circular cross-section is partially cut out in order to change the braking force according to the angle, the amount and position of the change in the braking force vary greatly due to a slight dimensional difference. In addition, it becomes more difficult to make the characteristics uniform.

[0005] The present invention has been devised to solve such problems of the prior art, and its main objects are as follows.
An object of the present invention is to provide a free-stop device capable of reliably preventing a leaf spring from coming off while suppressing an increase in manufacturing cost and obtaining uniform braking characteristics.

[0006]

In order to achieve such an object, the present invention has a leaf spring 3 which is curved so as to have a substantially U-shaped cross section. In a free stop device in which the shaft 1 is sandwiched between a pair of opposed leg plate portions 21 and a braking force is applied to the shaft by locking the leg plate portions to a bracket 2 pivotally connected to the shaft, The contact portion 21a with the shaft is formed in a flat plate shape with a straight cross section, and the contact portion 21a has a tip portion 2
A portion near 1b is provided with a retaining portion 26 that engages with either the shaft or the bracket to restrict the shaft from coming off the bracket.

[0007] According to this, it is possible to reliably prevent the leaf spring from coming out of the bracket, and since the contact portion of the leg plate portion with the shaft becomes a flat plate shape, it is possible to easily obtain high accuracy. Uniform braking characteristics can be obtained. In particular, even if the shaft has a substantially D-shaped cross section in which a part of a circular cross section is cut out, it is possible to suppress variations in the braking characteristics such as the amount of change in the braking force and the changed position. In addition, unlike the contact portion with the shaft, a high-precision portion is not required for the portion on the distal end side where the retaining portion is provided, so that the manufacturing process does not have to be so complicated. In particular, when the leaf spring is formed from a metal plate material, the manufacturing process can be simplified by obtaining the above-mentioned retaining portion by plastic working such as cutting and bending the leaf spring into a predetermined shape.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 and FIG. 2 show a first embodiment of a free stop device constructed according to the present invention.
This free stop device comprises a shaft 1, a bracket 2 for rotatably holding the shaft 1, and a leaf spring 3 which sandwiches the shaft 1 and applies a braking force to the shaft 1. As shown in FIG. The paper feed tray 4 interposed at the hinge portion of the paper feed tray 4 constituting the multi-stage paper feed tray of FIG.
Is stopped and held at an arbitrary inclination angle.

The shaft 1 is connected so that the connecting portion 6 at the end thereof cannot rotate relative to the supporting member 7 on the main body side with a predetermined play.
Are fixed to the base of the paper feed tray 4 with screws 8. FIGS. 1 and 2 show the mounting state shown in FIG.
FIG. 3 shows a state in which the paper feed tray 4 is rotated upward by 180 ° about the shaft 1 as shown by an arrow in FIG. It will rotate clockwise.
Although FIG. 3 shows only one end of the shaft 1, similarly, the other end of the shaft 1 is connected and supported by a support member on the main body side.

The bracket 2 is obtained by bending a metal plate, and has a bottom wall 12 provided with a screw hole 10 into which the screw 8 is screwed, and side edges of the bottom wall 12 facing each other. And a bearing portion 14 erected on a side edge of the bottom wall portion 12 orthogonal to the side wall portion 13. A locking hole 16 with which the leaf spring 3 is engaged is formed in the bottom wall portion 12. The bearing portion 14 has a bearing hole 17 through which the shaft 1 is inserted. The bracket 2 has an annular groove 18 formed on the peripheral surface of the shaft 1.
By attaching the retaining ring 19 to the shaft, displacement in the axial direction is restricted.

The leaf spring 3 is obtained by bending a metal plate material having required spring characteristics, and is bent so as to have a substantially U-shaped cross section. The leaf spring 3 is inserted between the two bearing portions 14 of the bracket 2 so as to sandwich the shaft 1 between a pair of leg plate portions 21 facing each other. Here, a pair of leaf springs 3 can be attached to the bracket 2.

Shaft 1 at leg plate 21 of leaf spring 3
Contact portion 21a is formed in a flat plate shape having a straight cross-sectional shape. Therefore, it is possible to easily obtain, with high accuracy, a separation dimension between the two leg plate portions 21 that affects the braking force on the shaft 1. Then, the shaft 1 accurately contacts the shaft 1 having a substantially D-shaped cross-section in which a part of the circular cross-section is cut out, and it is possible to suppress a variation in the braking characteristics such as a change amount and a change position of the braking force.

The distal end portions 21b of the pair of leg plate portions 21 are fitted into the locking holes 16 of the bracket 2 and locked at the opening edges thereof, whereby the relative rotation of the leaf spring 3 with respect to the bracket 2 is restricted. .

Therefore, as shown in FIG.
When the bracket 2 is rotated clockwise about the shaft 1 from a state in which the leg plate portion 21 contacts the cutout surface 23 of the shaft 1, the contact surface with the leg plate portion 21 becomes the cutout surface 2.
3 to the circumferential surface portion 24 having an arc-shaped cross section, the space between the two leg plate portions 21 of the leaf spring 3 is expanded, and a required braking force acts between the shaft 1 and the bracket 2. Thus, the leaf spring 3 and the shaft 1 can rotate relative to each other only when an external force exceeding the frictional force generated therebetween is applied. In addition, by forming the boundary between the cutout surface 23 of the shaft 1 and the circumferential surface portion 24 into a curved shape, the rotation operation can be smoothed.

At a portion of the leg plate portion 21 closer to the tip portion 21b than the contact portion 21a with the shaft 1, a protruding piece 26 that engages with the shaft 1 and prevents the leaf spring 3 from shifting is protruded inward. It is formed with. This protruding piece 26
Can be obtained by bending inward a convex portion punched into a predetermined shape. Here, a pair of projecting pieces 26 are provided so as to extend from both end edges in the axial direction of the shaft 1 in the both leg plate portions 21. As a result, the projection 26
By engaging the shaft 1 with the shaft 1, the upward movement of the leaf spring 3 in the drawing is restricted, and the leaf spring 3 can be reliably prevented from coming off.

FIGS. 4 and 5 show a second embodiment of the free stop device constructed according to the present invention.
Here, the protruding piece 32 for preventing the displacement of the leaf spring 31 is provided at the contact portion 33 a of the leg plate portion 33 with the flat shaft 1.
It is provided in a mode protruding outward from a portion closer to the distal end portion 33b. The protruding piece 32 is obtained by cutting and raising an intermediate portion of the leg plate portion 33 in the axial direction, more specifically, by making two cuts in a direction perpendicular to the axis of the shaft 1 and folding the intermediate portion outward. Can be

On the other hand, the bottom wall 36 and the side wall 37 of the bracket 35 are provided with locking holes 39 into which the projections 32 of the leaf spring 31 are fitted. Here, a locking hole 39 is provided so as to communicate with a locking hole 34 in which the distal end portion 33b is locked in order to regulate the relative rotation of the leaf spring 31. The protruding piece 32 is engaged with the upper edge portion of the locking hole 39, so that the upward movement of the leaf spring 31 in the drawing is regulated, whereby the leaf spring 31 is reliably prevented from coming off. In this embodiment, the other parts of the bracket 35 and the shaft 1 are the same as those in the first embodiment, and are denoted by the same reference numerals, and detailed description thereof will be omitted.

FIGS. 6 and 7 show a third embodiment of the free stop device constructed according to the present invention.
Here, a ring-shaped piece 42 surrounding the shaft 1 is provided so as to extend inward from the leg plate portion 43 in order to prevent the displacement of the leaf spring 41. This ring-shaped piece 42
Is obtained by punching into a predetermined shape and bending it into an L-shaped cross section. The leg plate 43 contacts the flat shaft 1 so that the leg plate 43 can accurately exhibit required spring characteristics. From the part 43a to the tip part 43b
It is connected at a closer portion, and is separated from the contact portion 43a with a notch groove 46 interposed therebetween. The base portion 44 of the ring-shaped piece 42 is formed with a curved portion 45 that is curved outward so as not to contact the peripheral surface of the shaft 1.

In this case, the inner peripheral edge of the center hole of the ring-shaped piece 42 is engaged with the shaft 1 so that the upward movement of the leaf spring 41 in the drawing is restricted, and the leaf spring 41 is reliably prevented from coming off. Further, the displacement of the leaf spring 41 downward in the drawing is also restricted. Note that, similarly to the above-described embodiment, the distal end portion 43b of the leg plate portion 43 is
And the relative rotation of the leaf spring 41 with respect to the bracket 2 is restricted. In addition, the bracket 2 and the shaft 1 are the same as those in the first embodiment, and are denoted by the same reference numerals, and detailed description thereof will be omitted.

FIGS. 8 and 9 show a fourth embodiment of the free stop device constructed according to the present invention.
Here, in order to prevent the displacement of the leaf spring 51, a ridge 52 is provided on the distal end portion 53 b of the leg plate portion 53 of the leaf spring 51 so as to protrude outward. This ridge 52
It is obtained by extruding an intermediate portion of the leg plate portion 53 in the axial direction by half blanking. The contact portion 53a of the leg plate portion 53 with the shaft 1 is formed in a flat plate shape as in the above embodiment.

On the other hand, the bottom wall 56 of the bracket 55
In order to regulate the relative rotation of the leaf spring 21, a locking hole 57 for locking the tip portion 53b of the leg plate portion 53 is formed, and a concave portion 58 in which the ridge 52 is fitted is formed at the opening edge. Have been. Thereby, the upward movement of the leaf spring 51 in the drawing is restricted, and the leaf spring 21 can be reliably prevented from coming off. In this embodiment, the bracket 5
The other parts of 5 and the shaft 1 are the same as those in the first embodiment, and are denoted by the same reference numerals, and detailed description thereof will be omitted.

The free stop device according to the present invention can be mounted on a hinge of a document holding panel or a maintenance opening / closing panel in addition to the paper feed tray of OA equipment such as a copying machine, a facsimile machine and a printer as described above. Can be applied. Further, it can be widely used as a means for preventing a rotating body from falling and an angle adjusting means, such as an opening / closing lid for an accessory case in a vehicle cabin or a posture adjusting mechanism of an in-vehicle display.

[0024]

As described above, according to the present invention, the leaf spring can be reliably prevented from coming off, and the contact portion of the leg plate portion of the leaf spring with the shaft is formed in a flat plate shape. Can be obtained. For this reason, uniform braking characteristics without variation can be obtained, and even when the shaft has a substantially D-shaped cross section, variations in the braking characteristics such as the amount of change in the braking force and the changed position can be suppressed. And, unlike the contact portion with the shaft, a high precision is not required for the tip side portion where the retaining portion is provided, so that the manufacturing process does not have to be so complicated,
The increase in the manufacturing cost can be kept small.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of a free stop device configured according to the present invention.

FIG. 2 is an exploded perspective view of the free stop device shown in FIG.

3 is a perspective view of a main part of a paper feed tray to which the free stop device shown in FIG. 1 is applied.

FIG. 4 is a sectional view showing a second embodiment of the free stop device configured according to the present invention.

5 is an exploded perspective view of the free stop device shown in FIG.

FIG. 6 is a sectional view showing a third embodiment of the free stop device configured according to the present invention.

FIG. 7 is an exploded perspective view of the free stop device shown in FIG. 6;

FIG. 8 is a sectional view showing a fourth embodiment of the free stop device configured according to the present invention.

9 is an exploded perspective view of the free stop device shown in FIG.

[Explanation of symbols]

 1 Shaft 2.35.55 Bracket 3.31.41.51 Leaf spring 21.33.43.53 Leg plate 21a.33a.43a.53a Contact part 21b.33b.43b.53b Tip part 26.32. (Retaining part) 42 Ring-shaped piece (retaining part) 52 Ridge (retaining part)

Claims (1)

[Claims] 1. A leaf spring having a U-shaped cross section and having a curved cross section. The leaf spring sandwiches a shaft between a pair of opposing leg plates and pivotally attaches to the shaft. A free stop device configured to apply a braking force to the shaft by locking the leg plate portion to a bracket, wherein a contact portion of the leg plate portion with the shaft is formed in a flat plate shape, and the contact portion is In the more distal part,
A free-stop device, comprising: a retaining portion that engages with one of the shaft and the bracket to regulate removal from the bracket.