JPH0524079B2 - - Google Patents

Description

Detailed Description of the Invention The present invention provides a lifter equipped with a pantograph mechanism and a linear actuator using an X-shaped cross link between a fixed base and a lifting platform, in which the lifting platform, that is, the floor plate, is lowered when stored. The purpose of the present invention is to provide a lifter that is easy to design and manufacture.

(Current technology) A lifter that drives a lifting platform by forcibly extending an X-shaped cross link is known, and a lifter with improved load characteristics (FIG. 8A) has also been proposed.
(Utility Application No. 61-128902) However, as shown in Figure 8B, the load characteristic of the latter is that the starting load is reduced compared to the known lifter, and the load is constant from the lowest position to the highest position of the lifting platform. As for the load characteristics, since the drive machine is also raised as the platform rises, there are limitations on the type of drive machine and there are disadvantages in that it is impossible to interlock multiple lifters.

Furthermore, in this type of lifter, it is desirable to lower the lifting platform (floor plate) and store the drive cylinder as horizontally as possible when stored.

To achieve this, the driving source was a hydraulic cylinder, and the rod of the cylinder was connected to one link via a rotating bracket, and the other link was formed with a concave slope that came into contact with a roller provided at the front end of the bracket. Lifter proposed (Jikko 50-
23971).

This device uses the extension force (pushing action) of a hydraulic cylinder.
The hydraulic cylinder is fixed to the rolling roller side of the X-shaped link (scissor link). In addition, since the lifting platform is raised and lowered by the rotational movement of the bracket due to the pressing action of the cylinder, a rotating bracket is essential. Since it stands upright, there is a limit to the low floor effect.

Furthermore, while it naturally requires extra parts, it also has a structure that reduces strength.

(Objective) The present invention provides a lifter that allows the cylinder to be in a horizontal state when stored, without using any extra parts or reducing strength, and which can be lowered to the lowest position. The present invention provides a lifter that can be started without overloading the linear actuator even when the linear actuator is in use.

Furthermore, since the actuators in this type of lifter are normally used in parallel synchronized operation of two or more, the present invention provides a lifter that can stably and reliably perform parallel synchronized operation.

(Structure) In the lifter according to the present invention, the central intersecting part of the X-shaped intersecting link is pivotally connected, one end of which is pivotally connected to a fixed base and a lifting platform, and a rolling roller is provided at the free end of the link. arc-shaped guide surfaces are formed on each opposing side of the free-end link, and a common support shaft of a pair of wedge rollers that rolls in contact with one of the guide surfaces is connected to a telescoping rod of a screw shaft type linear actuator. In the lifter, the cylinder of the linear actuator is pivotally mounted near the fixed side pivot of the cross link via a trunnion, and the wedge roller or the roller support shaft is attached to the base side of the lower arcuate guide surface of the link. A locking portion is provided.

In the present invention, the linear actuator refers to a screw shaft type linear actuator with a built-in motor or an externally driven screw shaft type linear actuator as shown in FIG.

(Example) The specific structure of the device of the present invention will be explained with reference to the drawings, together with its operation.

Reference numeral 1 denotes a fixed base, 2 an elevating table, and 3 an X-shaped pantograph mechanism using cross links, in which the central parts of a pair of link members 4 and 5 are connected by a pivot 6, and one end thereof is connected to the elevating table and the base. It has pivot points 7 and 8.

Reference numerals 9 and 10 denote rolling rollers provided at the free end of each link, which roll in contact with the base and the lifting platform surface.

A pair of arcuate guide surfaces 11 and 12 that swell with the same required curvature are formed on the opposing surfaces on the free end side of each link, and wedge rollers 13 and 14 that roll into contact with each other are rotatable on a common support shaft 15. It is set in.

Reference numeral 16 is a linear actuator, and the cylinder bottom side has a trunnion 21 mounted on the base near the pivot side of the cross link.
The telescopic rod 17 is pivotally mounted via the support shaft 16a, and the tip of the telescopic rod 17 is connected to the support shaft 15.

When the linear actuator 16 shortens, the wedge roller 1
3 and 14 are arcuate guide surfaces 11 and 12 that are in contact with each other.
The lifting platform 2 is raised by being guided by.

A roller hook 18 is formed on the base end side of the lower arcuate guide 12, and the roller 13 that has been rolled is formed with a roller hook 18.
After this is locked, the link 4 is directly driven to raise the lifting platform 2 as shown in FIG.

The arrangement relationship between each pair of left and right links and the linear actuator 16 is arbitrary, and a plurality of cylinders may be arranged on each side and along the links and these may be operated synchronously, or in small-scale cases. may have one cylinder installed in the center.

FIG. 5 is a plan view of a main part showing an example of parallel synchronous operation, in which a gearbox 22 as shown in FIG. The common transmission shaft 23 is driven by one motor 24.

According to such an interlocking drive system, synchronized operation of three or more units as shown in FIG. 7 can be designed very easily.

(Effects) As described above, according to the present invention, the wedge roller 13
The period during which the linear actuator moves on the arcuate guide surface is only during the initial process of the lifting platform's ascent, and after that, the load condition of the linear actuator is improved as shown in Fig. 8C until the linear actuator and the cross link are directly connected. Furthermore, synchronized operation of multiple units can be performed stably and smoothly.

[Brief explanation of the drawing]

Fig. 1 is a side view of the main part of the lifter of the present invention in the starting state, Fig. 2 is a side view of the main part when rising, Figs. 3 and 4 are partial side views of the roller locking part, and Fig. 5 is synchronous. A plan view showing the drive mechanism, Fig. 6 is a sectional view of a screw shaft type linear actuator with a gearbox connected, Fig. 7 is a plan view showing the connection state in case of multiple synchronous operation, and Fig. 8 shows load characteristics. FIG. 2... Lifting platform, 3... Pantograph mechanism, 12
... lower arcuate guide surface, 13 ... wedge roller,
18...Roller locking part, 16...Linear actuator, 2
0...Screw shaft type linear actuator, 23...Transmission shaft.

Claims (1)

[Claims] 1 The central crossing part of the X-shaped cross link is pivotally connected, one end of which is pivotally connected to a fixed base and a lifting platform, and a rolling roller is provided at the free end of the link, and each of the opposite ends of the free end side link A lifter in which an arcuate guide surface is formed on a side, and a common support shaft of a pair of wedge rollers that roll in contact with one of the guide surfaces is connected to a telescoping rod of a screw shaft type linear actuator, wherein the linear actuator A cylinder is pivotally connected to the fixed side pivot portion of the cross link via a trunnion, and a locking portion for the wedge roller or the roller support shaft is provided on the base side of the lower arcuate guide surface of the link. Low floor lifter.