JPH048154Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field This invention relates to a pantograph-type jack that is mainly carried in a car and used to hang onto a tire when changing a tire due to a puncture or the like.

2. Description of the Related Art Pantograph type jacks are mainly used for automobiles as described above. When hoisting a vehicle, since only the tires are replaced, one hoisting point is sufficient, and since the grounding point of the remaining tires is the center, the vertical movement line has a radius between the grounding point and the hoisting point. If the line of movement of the jack is a straight line, the line of action of the jack will be inconsistent, and unreasonable stress will be applied to the jack. Therefore, the jack is designed to be particularly robust in terms of structure so that it can withstand this. In order to solve this problem, as disclosed in Japanese Patent Laid-Open No. 55-7158, the centers of the pin holes in the mutually meshing teeth of the arm are provided asymmetrically so that the lines of movement coincide. There is.

Problems to be Solved by the Invention The above-mentioned conventional technology, which has a robust overall structure, is inevitably expensive. In addition, if the reference pitch circle of the tooth profile remains unchanged, but the pin hole center is simply shifted and the mutual meshing surfaces of the gears are moved, the meshing of the gears will be irregular and may cause wear, especially if used many times. , there is some wobbling and the original purpose cannot be achieved.

Means for Solving the Problem A base that is in contact with the ground, etc. and receives gravity, and a cargo receiving frame that is in contact with a vehicle, etc. and is loaded, are provided above and below, and between them, the inner end is connected to the supporting frame part on the base and the cargo receiving frame. At the same time, the gear parts provided on the inner ends are engaged with each other, metal is fitted on the opposite outer end, the upper and lower arms are connected in a parallelogram, and a threaded rod is passed through the metal. , At least one of them is screwed, and when the upper and lower arms are expanded and contracted by rotation of this threaded rod and the receiving frame is raised and lowered, the gear parts of the left and right arms are engaged with the support frame of the base and the receiving frame at the same level. The pantograph type jack is characterized in that one of the reference pitch circles is large and the other reference pitch circle is small, and is asymmetrically provided.

Function Since this device is constructed as described above, the reference pitch circles of the mutually meshing teeth are different, resulting in a difference in the rotation width, and the larger diameter side has a smaller rotation angle. Therefore, the lifting movement line becomes an arcuate line with the inner diameter on the larger diameter side, and therefore, when raising the vehicle, it can be made to substantially match the movement curve whose radius is the grounding point of the vehicle. Therefore, it can be loaded without difficulty.

Embodiments Hereinafter, this invention will be explained with reference to drawings showing examples of the invention. 1 is a pantograph type jack of this invention, 2 is a base, 3 and 4 are lower arms, and a large diameter gear part 5 whose inner ends are engaged with each other. and a small-diameter gear part 6, the inner end of which is rotatably supported on a support frame part 7 that stands up integrally on the base 2 by support shafts 8 and 9, and the gear parts 5 and 6 are meshed with each other. The respective outer ends are formed into caulked portions 10 and 11, and are rotatably connected to metals 12 and 13.

Reference numerals 14 and 15 designate upper arms, the inner ends of which are formed into a small diameter gear portion 16 and a large diameter gear portion 17;
Its inner end is pivotally supported in the receiving frame 18 by support shafts 19 and 20 diagonally to the gear parts 5 and 6 of the lower arms 3 and 4, with the large diameter gear part 17 and the small diameter gear part 16 corresponding to each other. , the outer ends are formed into caulked parts 21 and 22 and connected to metals 12 and 13.

In the above embodiment, when the distance between the support shafts 8 and 9 is l, the reference pitch circle of the large diameter gear part 5 and the small diameter gear part 6 is 1 for the large gear part 5 and 1 for the small diameter gear part 6.
2, and the ratio of their number of teeth is 9:8.

In addition, in the illustration, the reference numeral 23 is a receiving plate, 24 is a threaded rod, and 25 is a handle joint.

Since this idea is as described above,
When a handle (not shown) is connected to the joint 6 and the threaded rod 24 is rotated, the metal 12 moves closer to the metal 13 due to the screw action, so the lower arm 3,
4 and upper arms 14 and 15 are expanded into a parallelogram shape, and the cargo receiving frame 18 is raised relative to the base 1.
At this time, the gear parts 5, 6 and 17, 16 at the inner end of each arm are combined to have a large diameter and a small diameter at the same height, and a large diameter and a small diameter at the top and bottom of the same side, so that the threaded rod 24 Therefore, even if the metals 12 and 13 move closer to each other, the rotation angles are different between the large-diameter gear part and the small-diameter gear part, and there is a difference in the upright angle of the arms. The caulking part is metal 13 on the joint side of the handle.
As shown in FIG. 3, even if the operation starts from the same position as shown in FIG. 3, the upright angle is large as shown in FIGS. , move toward the rear end.
The angle of the threaded rod 24 relative to the ground also slopes from parallel to upward. However, since the gear portions 16 and 17 of the upper arms 14 and 15 are opposite to those of the lower arms 3 and 4, they are corrected in the vertical direction, and the receiving frame 18 remains parallel without changing its angle to the ground. Therefore, as shown in FIG. 2, the cargo receiving frame 18 maintains its horizontal position and moves up and down according to the arcuate movement line set by the size of the gear section.

Effects of the idea This idea is as described above, so
The gear portion at the inner end of the arm meshes smoothly and is natural, without uneven wear, and therefore can be operated smoothly.

[Brief explanation of the drawing]

The drawings show an embodiment of this invention, in which Fig. 1 is a partially cutaway side view, Figs. FIG. 4 is an enlarged partial side view. 1... Jacket, 2... Base, 3, 4... Lower arm, 5, 17... Large diameter gear part, 6, 16...
...Small diameter gear part, 7...Support frame part, 8, 9, 19,
20... Support shaft, 10, 11, 21, 22... Caulking part, 12, 13... Metal, 14, 15...
Upper arm, 18...Consignment receiving frame, 23...Consignment receipt, 2
4...Threaded rod, 25...Handle joint.

Claims (1)

[Scope of utility model registration request] A base that is in contact with the ground and receives gravity, and a load receiving frame that is in contact with and loaded with a vehicle etc. are provided on the upper and lower sides, and the inner end is pivotally supported between the support frame portion on the base and the load receiving frame, The gear parts provided at the inner ends are engaged with each other, the metal is fitted to the opposite outer end, the upper and lower arms are connected in a parallelogram, and a threaded rod is passed through the metal, and at least one of them is screwed. In a jack that expands and contracts the upper and lower arms by rotating this threaded rod and raises and lowers the receiving frame, the gear parts of the left and right arms that mesh at the same height with the support frame of the base and the receiving frame are placed at one reference pitch. A pantograph type jack characterized by having a large circle and a small standard pitch circle, which are asymmetrically arranged.