JPH04116098A - Pantagraph type power jack - Google Patents

Abstract

PURPOSE:To facilitate restart of operation by providing a formed wire on an inner wall face of upper and lower links of a pantagraph type power jack closely, and engaging a screw bar with a screw hole of a connecting pin by the formed wire at all times when a small diameter section of the screw bar is inserted into a female screw hole of the connecting pin and spins. CONSTITUTION:Four links 3, 3, 4, 4 are moved up and down due to the rotation of a screw bar 7 to be inserted into a screw hole of connecting pins 5, 6 which are connected with each link 3, 4. When a small diameter section 15 of the screw bar 7 reaches the screw hole of the connecting pin 5, idle running is done, and idle running is done at the descent limit so that unreasonable descent which exceeds that is eliminated. A formed wire 14 is provided on the inner wall face of the links 3, 4 close to the pin 5. Consequently, the screw hole of the connecting pin 5 is energized at all times in the direction where it contacts the screw section of the screw bar 7 and it is made so as to engage readily when the motion of the screw bar 7 is restarted.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an improvement of a pantograph type power jack, and more particularly to a power jack that has a relatively simple structure and is easy to manually operate.

(Prior Art) Changing a tire or attaching a tire chain to a car requires a jack to lift the car body, and the -II car is equipped with a pantograph type jack. This jack requires a great deal of effort to use in summer or during snowy seasons, as it requires a manual handle to be rotated to raise and lower the receiving plate, making it difficult for female drivers to operate. For this reason,
No. 88689 proposes a device for rotating the threaded rod of a manual jack using a DC motor. In this device, it is necessary to check the raising and lowering state of the jack when the motor is operating, and if this observation is neglected and the threaded rod is rotated beyond its limit position, the jack will be damaged. Furthermore, while operating the DC motor, it is necessary to hold the heavy motor by hand, which is quite a heavy labor.

(Problem to be Solved by the Invention) In contrast, in the power jack disclosed in Utility Application No. 2-54768 shown in FIG. When the connecting pin 52 reaches the position or the maximum lowered position, the acid threaded hole 53 of the connecting pin 52 fits into the small diameter portion of the threaded rod 51, and the threaded rod 51 idles, and the threaded rod does not rotate beyond its limit position.

When the electric motor rotates forward at the maximum lowered position, the coil spring 54 fitted to the threaded rod 51 always urges the threaded rod outward, so that the acid screw hole fitted in the front small diameter portion (not shown) 53 easily engages with the male threaded portion 55, and resumes the upward operation of the jack. On the other hand, at the maximum elevation position,
Since the front end of the coil spring 54 close to the rear small diameter portion 56 urges the connecting pin 52 outward, the acid threaded hole 53 engages with the male threaded portion 55 again, and the downward operation of the jack is resumed. In the power jack disclosed in U.S. Pat. This causes the jack to be constantly braked, making it difficult to raise and lower the jack smoothly when using it manually. Additionally, the structure of the jack is relatively complex, as the coil spring 54 sometimes biases the connecting pin 52 outward.

The present invention was proposed in order to further improve the power jack described above, and an object of the present invention is to provide a pantograph-type power jack that imparts restoring force to the jack by means of an elastic member disposed close to the inner wall surface or outer wall surface of the link. It is said that

(Means for Solving the Problems) In order to achieve the above object, the power jack 1 according to the present invention connects four links 3.4 to a diamond via a plurality of mounting pins 2, as shown in FIG. Two pins 5 and 6 are assembled into a shape and connect the upper link 3 and the lower link 4.
Although the threaded rod 7 is rotatably inserted through the front connecting pin 5, there is usually a screw hole 8 (third hole) into which the threaded rod 7 is screwed.
), and on the other hand, the rear connecting pin 6 is provided with a through hole (not shown) for a bearing. A stop ring 9 (FIG. 2) is fitted and secured to the threaded rod 7 in front of this through hole. The power jack 1 is an electric motor 1 installed at the rear.
0 rotates the threaded rod 7, thereby rotating the base 1
The receiving plate 12 is raised and lowered using 1 as a fulcrum. The power jack 1 is provided with a small diameter part 13 at the rear of the threaded rod 7, which is long enough to fit into the screw hole 8 of the connecting pin 5. On the other hand, the tip of the threaded rod 7 is also provided with a small diameter portion 15 long enough to fit into the acid screw hole 8 of the connecting pin 5, and the diameter of the small diameter portion 13°15 is smaller than the inner diameter of the acid screw hole 8. .

Wire springs 1 of an appropriate shape are installed on the inner wall surfaces of the links 3 and 4.
4 are arranged close to each other, and when the acid screw hole 8 is fitted into the small diameter portion 15 as shown in FIG. 3, the elasticity of the wirework spring 14 imparts a restoring force to the jack.

The shape and arrangement of this spring may be as shown in Fig. 2 or 3, or a rubber body (Fig. 4) may be installed in place of the filigree spring, and these are placed close to the outer wall of the link. It is also possible to do so.

Further, as shown in FIG. 5, opposing projections 16.18 of appropriate shapes may be formed on both side walls of the link 3.4. At least the protrusion 18 on the side that fits into it must be made of a steel material that is difficult to permanently deform. Good too. The protrusion 16.18 may be formed on the side wall of the link 3.4 by pressing or may be fixed to the link side wall by spot welding, and its planar shape and position may be arbitrary as long as it can be engaged with the link. You can also punch out the target. This protrusion is usually connected to the link 3,
4, but it is also possible to form it only on one side of the link 3 or 4 as shown in FIG. 7, and even in this case, at least the side into which it is fitted is made of steel.

(Function) In the power jack 1 according to the present invention, the screw rod 7 is rotated by the electric motor 10 installed at the rear, and when the jack reaches the maximum raised or lowered position, the acid screw hole 8 of the connecting pin 5 is inserted into the screw rod 7. The threaded rod 7 is fitted into the small diameter portion 13 or 15 and rotates idle, and the threaded rod is not rotated beyond its limit position. When the electric motor 10 is rotated forward at the maximum lowered position,
In the embodiment shown in FIG. 1, the filigree spring 14 imparts a restoring force to the jack 1, while in the embodiment shown in FIG. to give restoring force to Jyatsuki 1. As a result, by urging the connecting pin 5 inward through the link 3.4, the acid screw hole 8 fitted into the small diameter portion 15 easily engages with the tip of the male screw portion 31, thereby preventing jacking. Resume ascending operation. On the other hand, at the maximum raised position, the load held by the jack 1 urges the connecting pin 5 outward via the links 3 and 4, so the acid screw hole 8 engages with the rear end of the male screw part 31 again. , restart the jack's descending operation.

(Example) To explain the present invention based on the drawings, FIG. 1 shows the entire power jack 1 according to the present invention. power jacket 1
Here, four metal links 3 and 4 having a U-shaped cross section and having approximately the same dimensions are used, and through holes for pin insertion are formed at the front and rear ends of each link. Similar to this through hole, a through hole for pin insertion is provided between the base 11 and the receiving plate 12 with a U-shaped cross section.
Also, two pieces are formed at predetermined intervals. As a result, the four links 3 and 4 can be assembled into a rhombic shape via the plurality of mounting pins 2, and the upper link 3 and lower link 4 are partially overlapped, and the two pins with a larger diameter Connect with 5 and 6. Front connecting pin 5 with cutout flat surface 30
is provided with a threaded hole 8 in the diametrical direction for screwing in the threaded rod 7 in its middle part, while the rear connecting pin 6, which has a circular cross section, has a threaded hole 8 in its middle part for bearing the threaded rod 7. A through hole (not shown) is provided in the diametrical direction. A stop ring 9 (FIG. 2) is fitted and fixed to the threaded rod 7 in front of this through hole, and the ring prevents the threaded rod 7 from being pulled out or falling. The rear portion of the threaded rod 7 is provided with a small diameter portion 13 having a length that allows the acid screw hole 8 to fit into it, and the tip portion of the threaded rod also has a length that allows at least the acid screw hole 8 to fit into it. A small diameter portion 15 is provided, and the diameter of the small diameter portion 13.15 is required to be smaller than the inner diameter of the acid screw hole 8, and is usually approximately the same diameter. A male threaded portion 31 is carved between the small diameter portions 13.15, and the threaded rod 7 is inserted into the acid threaded hole 8 of the connecting pin 5.6 and the connecting pin so that the male threaded portion engages with the acid threaded hole 8. It is rotatably inserted into the through hole 6.

A filigree spring 14 with a double-shaped side surface is arranged close to the inner wall surfaces of the links 3 and 4. The horizontal bent portion 23 of the spring 14 is
The link 4 is riveted approximately in the middle of the inner wall surface, and the spring 14 is linearly extended obliquely upward from the bent portion, and then reaches the upper bent portion 24. The upper bent portion 24 has the jack 1
It comes into contact with the inner wall surface of the link 3 only when it reaches its maximum lowered position (see Figure 2). Usually, it is preferable that one pair of filigree springs 14 be provided on the inner wall surface of the link 4 with the threaded rod 7 in between. In the drawing, the spring 14 is installed only on the left link, but it is also possible to install it on the right link simultaneously or separately.

On the other hand, a gear box 22 and an electric motor 1o housed in a plastic housing are removably integrated and installed at the rear of the power jack 1.

The cylindrical gear box 22 has a horizontal insertion part 33 formed above it, and the U-shaped receiver pivoted on the rear connecting pin 6 inserts the protrusion 34 of the plate 21 into the insertion part 33, and then inserts the bolt. (not shown) is screwed in to hold the gear box 22.

In this holding state, the square rotating shaft of the gearbox is
It fits into a square hole (not shown) on the end face of the threaded rod.

A pair of projections 35 are formed on the rear circumferential wall of the gear box 22, and a pair of buckles 36 are attached to the front circumferential wall of the electric motor 10, so that the two are integrated during use by tightening the buckles. The electric motor 10 is a 12V DC motor whose rotation direction can be changed by switching a handheld switch, and the motor is wired to a plug (not shown) through the handheld switch. Power jack 1 is
After fitting the mounting adapter 40 corresponding to each vehicle onto the receiving plate 12, place it below a predetermined position on the vehicle body, and place it under the electric motor 10.
Connect the plug to the car's cigarette lighter socket. Next, press the appropriate button on the handheld switch,
The screw rod 7 is rotated by the electric motor 10, thereby raising and lowering the receiving plate 12 using the base 11 as a fulcrum.

The cord of electric motor 10 is quite long, so jack 1
You can work while checking the lifting and lowering status of the

In the power jack 1, the screw rod 7 is rotated in the forward direction by the electric motor 10, and when the jack 1 reaches the maximum raised position, the acid screw hole 8 fits into the small diameter part 13 of the screw rod 7, and the screw rod 7 idles. Therefore, the threaded rod 7 is not rotated beyond its limit position. Next, electric motor 10
When the threaded rod 7 is rotated in the opposite direction, the load held by the jack 1 forces the connecting pin 5 outward via the links 3 and 4, so that the acid threaded hole 8 is connected to the rear end of the male threaded part 31. The gears engage again and the jack 1 starts descending operation.

On the other hand, when the downward operation of the jack 1 by the reverse rotation of the threaded rod 7 continues and the jack reaches its maximum lowering position, the acid screw hole 8 fits into the small diameter part 15 and the threaded rod 7 idles, so the screw will not be rotated beyond its limit position. At this time, the upper bent portion 24 of the filigree spring 14 comes into contact with the inner wall surface of the link 3 and imparts restoring force to the jack 1.

Subsequently, when the threaded rod 7 is rotated in the forward direction, the restoring force of the jack 1 by the wirework spring 14 urges the connecting pin 5 inwardly via the links 3 and 4, so that the male threaded hole 8 is closed. It engages with the tip of jack 31 again and resumes the upward operation of jack 1.

When the electric motor 10 cannot be used due to a cord breakage accident, etc., the jack 1 connects the electric motor 10 and the gear box 2.
2 and manually rotate the threaded rod 7 using a commercially available manual handle. At this time, the upper bent portion 2 of the spring 14
4, as shown in FIG. 2, comes into contact with the inner wall surface of the link 3 only when the jack 1 reaches the maximum lowered position, and normally the elasticity of the spring 14 does not act on the threaded rod 7, so the jack 1 can be manually adjusted. It is relatively easy to go up and down.

The filigree spring used in the present invention may have the shape and arrangement shown in FIG. 2 or 3 in addition to the spring 14. For example, as shown in FIG.
If the lower part of the spring is fixed approximately in the middle of the inner wall surface of the link 4, the upper part of the spring will come into contact with the inner wall surface of the link 3 when the jack is at its maximum lowered position. Furthermore, as shown by the two-dot chain line in FIG. 2, when both ends of the wide semicircular spring 26 are fixed to the lower center of the inner wall surface of the lower link 4.4, the upper part of the spring circumference will be jerked to the maximum as shown in the figure. It comes into contact with the circumferential surface of the threaded rod 7 when in the lowered position.

The semicircular spring 26 is also capable of biasing the links 3, 4 outward when the jack is in its maximum raised position. base 1
1 has a U-shaped cross section, a horizontal U-shaped spring 27 is arranged between the inner end of the base 11 and the outer wall surface of the link 4,
If the lower part of the spring is fixed to the lower wall surface of the base 11, the upper part of the spring will come into contact with the outer wall surface of the link 4 when the jack is at the maximum lowered position.

Although the model U-shaped spring 27 is not shown, normally,
It is preferable to arrange one pair on the left and right.

In the present invention, instead of each of the filigree springs described above, a square rubber body 28 as shown in FIG. 4 may be LQMed between the links 4 and 4. The rubber body 28 may be bonded to the lower wall surface of the base 11 and has almost the same function as the semicircular spring 26 described above. Furthermore, if a pair of trapezoidal rubber bodies 29, 29 are installed between the inner end of the base 11 and the outer wall surface of the link 4, and the lower surface of the rubber bodies is adhered to the lower wall surface of the base 11, the rubber bodies can be It has almost the same function as the horizontal U-shaped spring 27. These rubber bodies may be arranged alone or in combination with the above springs.

In the modified example shown in FIG. 5, the link 3 is made of steel, and protrusions 16 are formed on both side walls of the link 4 so that the wall surfaces slope downward and inward. A protrusion 18 is formed which is inclined outwardly toward the protrusion 18 . As is clear from Fig. 6, the opposed protrusions 16 and 18 are arranged in such a position that they engage only at the jack maximum lowering position and rebound in the vertical direction, and do not engage in other positions (Fig. 5). reference). Opposing protrusion 16°18
is the front side wall of the left links 3, 4 and the right side links 3, 4.
The link portions overlap in the jack's maximum lowered position. The planar shape of the opposing projections 16,18 is an elongated trapezoid in the drawings, but this can be changed depending on the design. The size and wall inclination of the opposing projections 16 and 18 are set in consideration of the thickness and rigidity of the steel links 3 and 4 so that they will not be fixed as they are when they are engaged, and depending on the situation, In some cases, supplementary wire springs or rubber bodies are additionally installed. In the jack shown in Fig. 5, when the maximum lowered position is reached, the female threaded hole 8 fits into the small diameter portion 15 and the threaded rod 7 idles, so the threaded rod is not rotated beyond its limit position. . At this time, as is clear from FIG. 8, the opposing protrusions 16, 18 engage with each other and rebound in the vertical direction, imparting restoring force to the jack. Subsequently, when the threaded rod 7 is rotated in the forward direction, the restoring force of the jack is caused by the vertical repulsion of the projections 16 and 18, and the connecting pin 5 is urged inward via the links 3 and 4, thereby tightening the female thread. The hole 8 engages with the tip of the male threaded portion 31 again, and the upward operation of the jack is restarted.

The protrusion in the modification shown in FIG. 5 may be formed only on one of the upper or lower links 3, 4. For example, as shown in FIG. 7, the inward projections 42 are formed along the upper edges of both side wall surfaces of the link 40, and the inclined cut edges 43 are provided on the upper edges of both side wall surfaces of the link 3. The link 3 is made of steel. The wall surface of the inward protrusion 42 and the cut side 43 are as follows:
The jack makes contact only at the maximum lowered position, repelling the link 3.4 in the vertical direction. The inward protrusion in link 4 is
If it is formed at the position 44 shown by the two-dot chain line in FIG. 7, the wall surface of the inner protrusion 44 and the upper edge 45 of the link 3 will be at the jack maximum lowering position without any processing on the link 3. The contact causes links 3.4 to rebound in the vertical direction. In these modifications, instead of forming the inner protrusion on the link 4, only the outer protrusion may be formed on the link 3 by spot welding.

(Effects of the Invention) When the power jack according to the present invention rotates the threaded rod with the electric motor installed at the rear, the rotation of the threaded rod is rarely braked, and the rotation is smooth, even when manually operated. The lifting and lowering operation of the jack is smooth. When the jack reaches its maximum raised or lowered position, the female threaded hole of the connecting pin fits into the small diameter part of the threaded rod and the threaded rod idles, so the threaded rod will not be rotated beyond its limit position. . The power jack of the present invention has a relatively simple structure and is easy to repair even if it breaks down.

[Brief explanation of the drawing]

Fig. 1 is a side view showing a power jack according to the present invention, Fig. 2 is a partially cutaway side view of the jack in Fig. 1 at the maximum lowered position, and Figs. 5 is a side view showing another modified example; FIG. 6 is a side view of the jack in FIG. 5 at its maximum lowered position; FIG. FIG. 8 is a cross-sectional view taken along the line IV--IV in FIG. 6, and FIG. 9 is a cross-sectional view showing the main parts of a conventional power jack at the maximum raised position. 1...Power jack, 2...Mounting pin, 3.4.
...Link, 5.6...Connecting pin, 7...Threaded rod,
8... Female screw hole, 10... Electric motor, 11...
Base, 12... Reception plate, 13... Small diameter part, 14...
- Wirework spring, 15...small diameter part, 16.18... opposing protrusion part.

Claims (1)

[Claims] 1. Assemble four links in a rhombic shape via mounting pins, and insert a threaded rod into the two pins that overlap and connect the upper and lower links so as to be rotatable, and install the threaded rod using an electric motor. This is a pantograph-type power jack that raises and lowers a receiving plate using the base as a fulcrum with the rotation of The diameter of the small diameter part is smaller than the inner diameter of the female screw hole, and a wire spring is arranged close to the inner or outer wall surface of the link,
When the female threaded hole of the connecting pin fits into the small diameter part of the tip of the threaded rod, a restoring force is applied to the jack by the elasticity of the wirework spring that is in contact with the inner wall surface of the link, the outer wall surface, or the threaded rod, and the female screw A power jack that restarts the engagement between the hole and the male thread of the threaded rod. 2. The power jack according to claim 1, wherein a rubber body is installed inside or outside the jack in place of the spring. 3. Assemble the four links in a diamond shape through the mounting pins, and insert the threaded rod into the two pins that connect the upper and lower links so that they can rotate freely.The base is used as a fulcrum by rotating the threaded rod using the electric motor. This is a pantograph-type power jack that raises and lowers a receiving plate as a power jack, and has a small diameter part at the tip and rear part of the threaded rod that is long enough to fit into the female screw hole of the connecting pin, and the diameter of the small diameter part is The inner diameter of the connecting pin is smaller than the inner diameter of the screw hole, and opposing protrusions are formed on both side walls of the upper and lower links, at least the protrusions on the fitting side are made of steel, and the female screw hole of the connecting pin is formed on the tip of the threaded rod. When the power jack is fitted into a small diameter part, the opposing protrusions engaged with each other rebound in the vertical direction to apply a restoring force to the jack, thereby restarting the engagement between the female threaded hole and the male threaded part of the threaded rod. 4. The power jack according to claim 3, wherein the protrusion is formed on only one of the upper and lower links.