JPS622237Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an arm constituting a diamond-shaped link of a pantograph-type jack.

(Prior Art) Conventionally, an arm 3 and an arm 5, each having a substantially U-shaped cross section at one end, are screwed into a nut 12, and the other end is connected to another arm 4 and an arm 6.
A threaded rod 14 is supported on a metal 13 which is pivotally supported.
In a pantograph jack that raises and lowers the loading platform 2 by raising and lowering each arm as the screwing position changes, the load received by the loading platform 2 is usually an eccentric tilt load, and the degree of eccentricity or As the magnitude of the load increases, the tooth-shaped portions 3a, 4a formed on the side where the four arms 3, 4, 5, 6 constituting the rhombic link are pivotally supported with respect to the cargo receiving platform 2 or the pedestal 7. , 5a, 6a are gear-engaged with each other. It is important to reduce the contact surface pressure applied to the engaging portions.

To deal with this, arm 3 of each arm
To describe this as a representative example, as shown in FIG. 2, the tooth-shaped portion 3a formed at the end of the arm 3 on the side on which the pedestal 7 is pivotally supported is a flange extending approximately perpendicularly from the end of the arm 3. By forming a tooth surface on the continuous outer surface of the part 3b, the contact surface pressure of the tooth-shaped part can be reduced without increasing the overall thickness of the arm 3 and without causing a significant increase in weight.

(Problem to be Solved by the Invention) However, the pivot holes through which the pins 8, 9, 10, 11 for pivoting each arm to the cargo receiving platform 2 or the pedestal 7 pass through, for example, the pivot hole of the arm 3, 3c
To explain this, as shown in FIG. 3, the center P in the extending direction of the flange 3a, which is the center of the load acting surface, and the center Q in the penetrating direction of the pivot hole 3c, which is the center of the pressure receiving surface of the pivot hole.
Since these do not coincide with the vertical line, when a load is applied to the tooth-shaped portion of the arm, a force is generated that twists the arm, resulting in a drawback that the strength is not sufficient.

Therefore, an object of the present invention is to eliminate the above-mentioned drawbacks.

[Structure of the idea]

In order to solve this problem, the present invention has a pair of side walls that are approximately U-shaped in cross section and face each other, and is pivoted to a cargo receiving stand or a pedestal through pivot holes coaxially formed in the both side walls. In the arm of the pantograph jack constituting the diamond-shaped link, the tips of the arm on both pivot hole sides are folded back along the inner surface of each side wall, extending in a direction substantially perpendicular to the side wall, and having at least the thickness of the plate. Flanges approximately twice as thick are provided on each side wall, tooth surfaces are formed on the outer surfaces of both flanges around the pivot holes, and each side wall around the pivot holes is formed into a conical shape with respect to the extending direction of each flange. A measure was taken of deforming it into a trapezoid shape and aligning the center of each of the pivot holes in the penetration direction with the center of the flange in the thickness direction on a vertical line.

(Function) As described above, with the means of the present invention, each side wall of the arm around the pivot hole is deformed into a truncated conical shape in the extending direction of each flange on which the tooth surface is formed, and The center is aligned with the center of the flange in the thickness direction on a vertical line.

As a result, twisting of the arm due to the applied load can be eliminated, and the arm can have sufficient strength.

(Embodiment) A preferred embodiment of the present invention will be described below with reference to the drawings.

In one embodiment of the present invention, as shown in FIG. 4, which corresponds to FIG. 3 which is a conventional example, the tip of the side wall of the arm 3, which has a substantially U-shaped cross section, is machined by upsetting or the like from the tip to the inner surface of the side wall. The flange 3b is folded back along the side wall to form a flange 3b extending substantially perpendicular to the side wall and having a thickness approximately twice the thickness of the side wall. Tooth-shaped portion 3 with tooth surfaces lined up on the continuous outer surface of this flange 3b
form a.

Furthermore, the outer circumferential portion 3d of the pivot hole 3c through which the pin 8 that pivots the arm 3 to the pedestal 7 passes through is punched out so that it does not become deformed into a truncated conical shape, and the center Q of the pivot hole 3c in the penetrating direction is aligned with the extension of the flange 36. It is aligned with the center P in the extending direction of the flange 3b on the vertical line without any displacement in the extending direction.

Therefore, since the center P in the extending direction of the flange 3a, which is the center of the load acting surface, and the center Q in the penetrating direction of the pivot hole 3c, which is the center of the pressure receiving surface of the pivot hole, are aligned on a vertical line, the tooth-shaped portion of the arm No force is generated to twist the arm when a load is applied to it, and the strength of the arm can be improved. In addition, since the outer peripheral portion of the pivot hole 3c is deformed into a truncated cone shape in the flange extension direction, this deformed portion also acts as a reinforcing rib on the arm side wall, which is advantageous for improving the strength of the arm. It is.

The arm 3 has a substantially U-shaped cross section and has a pair of side walls facing each other. Although one side wall of the arm 3 has been described, the other side wall is similarly configured.

In the embodiment, the arm 3 has been described, but it goes without saying that the other arm 4, which is pivotally supported on the pedestal 7, can be constructed in the same manner.

Further, similar effects can be achieved even if the present invention is applied to an arm that pivotally supports a pedestal. Furthermore, it is even more effective if it is applied to each of the arms on the side that pivotally supports the pedestal and the cargo receiving platform.

[Effect of idea]

As detailed above, in the arm of the present invention, each side wall around the pivot hole is deformed into a truncated cone shape in the direction in which each flange extends. Thereby, this truncated conical deformed portion also acts as a reinforcing rib on the side wall of the arm, and there is an advantage that the strength around the pivot hole where the load is concentrated on the side wall of the arm can be improved.

[Brief explanation of the drawing]

Fig. 1 is an overall view showing a conventional example of a pantograph type jack, Fig. 2 is an enlarged perspective view of the pivot side of the jack arm shown in Fig. 1, and Fig. 3 is a cross section taken along the - line in Fig. 2. FIG. 4 is an explanatory diagram showing an embodiment of the present invention, and FIG. 5 is a right side view of FIG. 4. 1... Jyatsuki, 3, 4, 5, 6... Arm,
2... Loading platform, 7... Pedestal, 3a, 4a, 5a,
6a... tooth shaped part, 3b... flange, 3c...
Pivot hole, 3d...outer peripheral portion, P...center in the extending direction of the flange, Q...center in the penetrating direction of the pivot hole.

Claims (1)

[Claims for Utility Model Registration] It has a pair of side walls that are substantially U-shaped in cross section and face each other, and is pivoted to a cargo receiving stand or a pedestal through pivot holes coaxially formed in the both side walls to form a rhombic link. In the arm of the pantograph-type jack that constitutes the A flange about twice as thick is provided on each side wall, tooth surfaces are formed on the outer surfaces of both flanges around the pivot hole, and each side wall around the pivot hole is shaped like a truncated cone in the direction in which each flange extends. The arm of a pantograph-shaped jack is deformed into a shape, and the center of each of the pivot holes in the penetration direction is aligned with the center of the flange in the thickness direction on a vertical line.