JPH08259190A - Pantagraph jack - Google Patents

Abstract

PURPOSE: To improve operativity of a pantagraph. CONSTITUTION: A support hole 69 is provided on a connecting shaft 17 connecting an upper arm and a lower arm to each other, grooves 61, 63 for fixed pins are provided on a movable screw member 49, an engagement hole 71 and a pin 73 for fixture free to insert into and extract from the engagement hole 71 are provided on the connecting shaft 17, a non-female screw part 67 is provided on a female screw part 65 of the connecting shaft 17, a non-female screw part 59 is provided on a movable female screw part 57 of the movable screw member 49, and a non-male screw part 77 is provided on a male screw part 75 of a screw shaft 25. A screw released state is made when the movable screw member 49 is properly operated and the non-female screw part 59 is made to face against the non-female screw part 67 in the shaft direction, and a screw connected state is made when the non-female screw part 59 is made to face against the female screw part 65. Fixture of the movable screw member 49 is carried out by engaging the movable screw member 49 with the groove 61 or the groove 63 for the fixed pins by inserting the pin 73 for fixture into the engagement hole 71.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pantograph jack for lifting an automobile body or the like.

[0002]

2. Description of the Related Art As a conventional pantograph jack,
For example, there is one as shown in FIG.
999). This pantograph jack has a base 1, a pair of lower arms 3 and 5, and a pair of upper arms 7 and
9 and a receiving portion 11. The lower ends of the pair of lower arms 3 and 5 are rotatably supported by the base 1 via pins 13 and 15. The lower ends of the upper arms 7 and 9 are rotatably coupled to the upper ends of the lower arms 3 and 5 via coupling shafts 17 and 19 as a pair of coupling members. The receiving portion 11 is rotatably supported on the upper ends of the upper arms 7 and 9 via pins 21 and 23. Receiver 1
1 is provided with a groove portion 12. The pair of connecting shafts 1
One end side of the screw shaft 25 is rotatably supported by one of 7, 7 and the tip end side of the screw shaft 25 is screwed into the other. The screw shaft 25 is provided so as to project from the outside of the one connecting shaft 17, and a handle joint 27 is integrally provided.

Then, when the receiving portion 11 is aligned with, for example, the side sill of the vehicle body and the handle joint 27 is rotated by a jack handle (not shown), both connecting shafts 17, 19 are connected.
Can move so that they approach each other, and the receiving portion 11 rises to lift the body of the automobile.

[0004]

By the way, when the vehicle body is jacked up by the above pantograph jack, the downward force applied to the jack increases as the screw shaft 25 is rotated to raise the vehicle body upward, and the screw shaft 25 is rotated. The operation force to rotate 25 was large. For this reason, conventionally, the screw pitch of the screw shaft 25 has been reduced to suppress an increase in operating force. However, if the pitch of the screw shaft 25 is reduced, the ascending speed of the jack becomes slower with respect to the rotation speed of the screw shaft 25, which causes the following problems. That is, the screw shaft 25 must be rotated in a state in which the rising speed is slow even in the unloaded state from the folded state of the jack to the side sill of the vehicle body side hitting the side sill.
Even if the distance between 1 and the side sill is small, the receiving part 11 cannot be applied to the side sill unless the screw shaft 25 is considerably rotated, and the screw shaft 25 needs to be operated considerably, and the jack-up operation is extremely complicated. There was a problem of becoming.

On the other hand, there has been proposed a structure in which the male screw and the female screw are unscrewed until the receiving portion is brought into contact with the vehicle body side, so that the male screw can be easily operated (Actual No. Sho 63-119).
No. 593).

That is, the main part of this structure is shown in FIG. As shown in FIG. 8A, the upper and lower arms 7 and 3 are rotatably coupled to a bracket body 29 as a connecting member, and a storage portion 35 having inclined guide surfaces 31 and 33 is provided in the bracket body 29. ing. A pair of upper and lower nut members 37, which are divided in half, are provided in the storage portion 35. The nut member 37 is rotatably stored in the storage portion 35, and the female screw portion 39 is screwed onto the screw shaft 25 (b). The rotation operation is performed between the state (1) and the state (a) of releasing. Further, the nut member 37 is provided with a plate-shaped spring 41, and the nut member 37 is rotationally biased in a direction in which the female screw portion 39 is screwed as shown in (b) by the biasing force of the plate-shaped spring 41.

Therefore, when jacking up, the bracket main body 29 is pulled in the direction of arrow A when the receiving portion is pulled up in the unloaded state and the upper and lower arms 7, 3 move in the extension direction, and the guide surface 31 presses the nut member 37. . By this pressing, the nut member 37 rotates in the direction around the hour hand in the figure against the biasing force of the plate spring 41, and the screw engagement of the female screw portion 39 with the screw shaft 25 is released as shown in (a). Therefore, the receiving part can be pulled up smoothly after that,
The receiving portion can be brought into contact with the side sill on the vehicle body side simply by pulling up. If the lifting of the receiving part is released at this point, the receiving part and the upper and lower arms 7 and 3 are slightly lowered,
The nut member 37 is slightly returned in the direction opposite to the arrow A direction of (a). By this return, the guide surface 33 side contacts the nut member 37, and the urging force of the plate-shaped spring 41 causes the nut member 37 to rotate around the counterclockwise hand, and the female screw portion 39 is screwed onto the screw shaft 25. In this state, by rotating the screw shaft 25, the receiving portion and the upper and lower arms 7 and 3 can be moved upward.

However, in such a structure, when the receiving portions 7 and 3 are moved down, the nut member 37 is moved to the screw shaft 2.
Since it is always screwed to the receiving part 5, the receiving part and the upper and lower arms 7 and 3 must be in the retracted state by rotating the screw shaft 25 even after the receiving part is disengaged from the vehicle body side and becomes unloaded. For this reason, when the screw pitch of the screw shaft 25 is reduced in order to reduce the operating force, the operation during storage becomes complicated, and there is a limit to improving the ease of operation.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a pantograph jack capable of achieving both reduction of jack-up operation force and improvement of operability.

[0010]

In order to solve the above-mentioned problems, the invention of claim 1 has a pair of lower arms whose lower ends are rotatably supported by a base and upper ends of the lower arms, one of which is a female screw. The other end is rotatably supported at its lower ends via a pair of connecting members having through holes, and its upper ends are directly or indirectly rotatably supported, and the upper end side receives a jack-up counterpart side. A pair of upper arms, a male screw part screwed into the female screw part of the one connecting member, and a rotation operating part rotatably and immovably supported in the through hole of the other connecting member. A screw shaft is provided between the female screw portion of the one connecting member and the male screw portion of the screw shaft, and a screwing / interrupting mechanism that releases the screwing operation and is connectable is provided, and the upper and lower arms are raised. That a biasing member that biases the And butterflies.

A second aspect of the present invention is the pantograph jack according to the first aspect, wherein the screw engagement and disengagement mechanism is provided concentrically with the female screw portion of the one coupling member, and is rotatable about the axis of the coupling member. And a movable screw member having a movable female screw portion at the shaft center portion, which is rotatable and can be fixed by a fixing means, and at least one pair is provided on the outer periphery of the male screw portion at symmetrical positions with the shaft center interposed therebetween. A male threadless portion and at least a pair of female threads corresponding to the male screwless portion and the female threaded portion and the movable female threaded portion so as to partially leave the female threaded portion and the movable female threaded portion on the inner circumference of the female threaded portion and the movable female threaded portion at symmetrical positions with the axial center interposed therebetween. It is characterized by having a non-existing portion.

A third aspect of the present invention is the pantograph-type jack according to the second aspect, wherein the movable screw member has a cylindrical portion whose outer periphery is circular and has the movable female screw portion concentrically. A support hole which is provided at one end of the tubular portion and is provided with a handle for rotating operation, and which is provided concentrically with the female screw portion on the one coupling member to rotatably fit the tubular portion of the movable screw member. It is characterized by having.

According to a fourth aspect of the present invention, in the pantograph jack according to the third aspect, the fixing means is provided on the tubular portion and a releasable locking member provided on the side of the one coupling member. It is characterized by comprising at least a pair of engaging portions respectively corresponding to the movable female screw portion and the female screwless portion.

According to a fifth aspect of the invention, there is provided the pantograph jack according to the fourth aspect, wherein the locking member is insertably and removably inserted into a locking hole penetrating from the outer surface of the connecting member to the support hole. The engaging portion is a fixing pin groove which is provided on the outer peripheral surface of the cylindrical portion of the movable screw member and engages with the fixing pin.

A sixth aspect of the present invention is the pantograph jack according to the second to fifth aspects, wherein the female screwless portion is provided within a range of about 90 ° of the inner circumference, and the male screwless portion is the It is characterized in that it is provided in a wider range than the distribution of about 90 ° on the outer circumference.

[0016]

According to the first aspect of the present invention, the upper and lower arms are urged by the urging force of the urging member by releasing the screwing between the female screw portion side of the connecting member and the male screw portion of the screw shaft by the screwing connecting / disconnecting mechanism. Is urged toward the ascending side, and the receiving part is raised so that it can contact or approach the opponent side of the jack-up.

Then, by connecting the screwing of the female screw portion and the male screw portion by the screwing connecting / disconnecting mechanism, the upper and lower arms can be further moved to the upward side by the rotation of the screw shaft, and the other side can be jacked up. You can Therefore, the screw shaft does not participate in the jack-up until the receiving portion hits the other side of the jack-up or approaches the other side, so that the screw pitch of the screw shaft can be reduced.

According to the invention of claim 2, in addition to the function of the invention of claim 1, the female screwless portion of the movable screw member is axially opposed to the female screwless portion of the connecting member, and the movable screw member is fixed by the fixing means. . Further, the male screw portion of the screw shaft is made to face the female screwless portion of the connecting member. As a result, mutual screwing of the female screw portion and the male screw portion by the screwing connection / disconnection mechanism can be performed.

Further, the fixing of the movable screw member by the fixing means is released, the movable screw member is rotated to shift the female screwless portion in the circumferential direction with respect to the female screwless portion of the connecting member, and the movable means is moved at that position by the fixing means. Fix the screw member. This is substantially the same as the state in which there is no female screw-free portion in the connecting member. That is, when the screw shaft is rotated, the distal end side of the screw shaft is screwed into the movable female screw portion of the movable screw member and at the same time screwed into the female screw portion of the connecting member, and thereafter the upper and lower arms are further extended by the rotation of the screw shaft. The receiving part can be raised. This allows the other side to be jacked up.

According to the third aspect of the present invention, in addition to the operation of the second aspect of the invention, the movable screw member can be rotatable by fitting the cylindrical portion of the movable screw member into the support hole of the connecting member. Further, when the movable screw member is rotated, it can be operated by its handle.

According to the invention of claim 4, in addition to the operation of the invention of claim 3, the movable screw member is rotated so that the female screwless portion thereof faces the female screwless portion of the connecting member, and the locking member is provided on one side of the tubular portion. The mutual screwing can be released by engaging with the engaging portion of. Also, remove the locking member,
By rotating the movable screw member again, the non-threaded portion of the movable screw member is opposed to the female screw portion of the connecting member, and the locking member is engaged with the other engaging portion so that the mutual threaded connection state can be established.

According to the invention of claim 5, in addition to the operation of the invention of claim 4, the fixing pin groove is provided on the outer peripheral surface of the cylindrical portion of the movable screw member by inserting the fixing pin into the locking hole of the connecting member. Can be selectively engaged to allow unscrewing and connection.

According to a sixth aspect of the present invention, in addition to the effects of the second to fifth aspects, the female screwless portions of the connecting member and the movable screw member are provided within a range of about 90 ° distribution on the inner circumference, and the male screw of the screw shaft is provided. The non-existing portion is provided in a wider range than the distribution of about 90 °. Therefore, when the male screw portion of the screw shaft faces the connecting member and the female screwless portion of the movable screw member, the male screw portion can relatively move in the axial direction without difficulty.

[0024]

Embodiments of the present invention will be described below. The same components as those in FIG. 6 will be described with the same reference numerals and redundant description will be omitted.

FIG. 1 is a side view of a pantograph jack according to an embodiment of the present invention. As shown in FIG. 1, the pantograph jack according to the embodiment of the present invention also comprises a base 1, lower arms 3, 5, upper arms 7, 9, a receiving portion 11, a screw shaft 25 and the like.

On the other hand, in the embodiment of the present invention, the screw connecting / disconnecting mechanism 43 is provided between the connecting shaft 17 which is one connecting member and the screw shaft 25. Further, torque springs 45 and 47 are attached to both connecting shafts 17 and 19 as biasing members. Lower arm part 4 of one torque spring 45
5a engages with an engagement protrusion 3a provided on the lower arm 3. Further, the upper arm portion 45b is engaged with the engagement protrusion 3b provided on the upper arm 7. Similarly, the lower arm portion 47a and the upper arm portion 47b of the torque spring 47 are engaged with the engagement protrusions 5a and 9a provided on the other lower arm and upper arm 5 and 9, respectively. Therefore, the upper and lower arms 7, 9, 3, 5 are set by the torque springs 45, 47.
Is configured to urge the rising side.

Details of the screw engagement / disconnection mechanism 43 are shown in FIGS.
It looks like. That is, the screw connecting / disconnecting mechanism 43 includes the movable screw member 49 and the fixing means 51.

The movable screw member 49 includes the tubular portion 53 and the handle 5.
It consists of 5. The cylindrical portion 53 has an outer periphery formed in a circular cross section, and has a movable female screw portion 57 concentrically. The movable female screw portion 57 is provided along the entire axial length of the tubular portion 53, and a female screwless portion 59 is provided so as to partially leave the movable female screw portion 57 in the circumferential direction. The handle 55 is integrally provided at one end of the tubular portion 53. Fixing pin grooves 61 and 63 are provided as at least a pair of engaging portions on the outer peripheral surface of the cylindrical portion 53.

A female screw portion 65 is provided on the connecting shaft 17. The female screw portion 65 is also provided with a female screwless portion 67. Further, the connecting shaft 17 is provided with a support hole 69 concentric with the female screw portion 65. The support hole 69 has a diameter larger than that of the female screw portion 69 and is formed in a size to fit the tubular portion 53 of the movable screw member 49, and has an opening 69a on the movable screw member 49 side. The abutment wall 69b is provided on the 65 side. A locking hole 71 is formed at one side of the support hole 69 to vertically penetrate the connecting shaft 17. For example, a split pin-shaped fixing pin 7 is provided in the locking hole 71.
By inserting 3, the fixing pin grooves 61, 63
Together with this, the fixing means 51 is configured. Therefore, the movable screw member 49 is fitted in the support hole 69 and rotatable about the axis, and can be fixed by the fixing means 51.

The screw shaft 25 is provided with at least a pair of male screwless portions 77 having a two-face width on the outer periphery of the male screw portion 75 at symmetrical positions with the axis centered therebetween. This male screwless part 77
Are provided in a wider range than the distribution of the outer circumference of the screw shaft 25 by about 90 ° in this embodiment. The male screwless portion 77 can be provided in a range of about 90 °.

Details of the fixing means 51 are as shown in FIGS. 3 is a cross-sectional view of the connecting shaft 17 at the portion of the fixing pin 73, and FIG.
It is sectional drawing in a line arrow. As shown in FIGS. 3 and 4, the locking hole 71 penetrates the connecting shaft 17 at one side of the support hole 69, and a part thereof also penetrates the support hole 69. One of the fixed pin grooves 61 and 63 corresponds to the movable female screw portion 57, and the other 63 corresponds to the female screwless portion 59. The fixing pin grooves 61 and 63 are formed by grooves having flat bottoms as shown in FIG. Therefore, the fixing pin grooves 61 and 63 can be easily provided by cutting at the time of processing, and the manufacturing is easy. Then, the fixing pin 73 is inserted into the locking hole 71, for example, the fixing pin groove 61.
Is engaged with.

The range of the female screwless portions 59 and 67 is shown in FIG.
It looks like. For example, the female threadless portion 67 of the connecting shaft 17 is as shown in FIG. 5A when viewed in cross section.
That is, the female screw portion 65 and the female screwless portion 67 are provided in a range of about 90 ° distribution. The movable screw member 49
The movable female screw portion 57 and the female screwless portion 59 are also provided in the range of 90 ° distribution as shown in FIG. 5B. The male threadless portion 77 may be provided entirely in the axial direction of the male threaded portion 75, or may be partially provided on the tip side of the male threaded portion 75. When partially provided, the male screwless portion 7
The axial boundary between 7 and the male screw portion 75 abuts the female screw portion 65, so that the screw shaft 25 and the connecting shaft 17 can be axially positioned. In this case, the upper and lower arms 7, 9,
When the 3, 5 and the receiving portion 11 move upward in the jack-up direction, the upward movement more than a predetermined amount can be restricted by the positioning between the screw shaft 25 and the connecting shaft 17, and immediately before the receiving portion 11 hits the side sill. It is also possible to position automatically.

Next, the operation will be described.

(At no load increase) First, when jacking up, in the unloaded state until the receiving portion 11 hits the side sill on the vehicle body side, the male screw portion 75, the movable female screw portion 57, and the female screw portion 65 by the screw connecting and disconnecting mechanism 43 are connected. Unscrew. That is, the fixing pin 73 is pulled out from the locking hole 71, the handle 55 of the movable screw member 49 is operated, and the tubular portion 53 of the movable screw member 49 is rotated around the axis with respect to the support hole 69. By this rotation, the female screwless portion 59 of the movable screw member 49 is axially opposed to the female screwless portion 67 of the connecting shaft 17.
This is seen from the axial direction as shown in FIG. In this state, if the fixing pin 73 is inserted into the locking hole 71,
The fixing pin 73 has the fixing pin groove 61 at the supporting hole 69.
To prevent the tubular portion 53 from rotating and coming off.

The movable screw member 49 can also be taken out of the support hole 69 and inserted again into the support hole 69. When the tube portion 53 is inserted into the support hole 69, the tip of the tube portion 53 abuts. The movable member 49 is positioned by hitting the wall 69b. In this positioning state, the fixing pin groove 61 or 63 is aligned with the locking hole 71 in the axial direction.

Next, when a jack handle (not shown) is engaged with the handle joint 27 of the screw shaft 25 to rotate it,
The male screw portion 73 of the screw shaft 25 faces the female screwless portions 59 and 67, and the male screwless portion 77 moves the movable female screw portion 57.
And, the screwing is released at the time when it faces the female screw portion 65.

Then, the male screw portion 75 and the movable female screw portion 57
When the screwing with the female screw portion 65 is released, the upper and lower arms 7, 9,
3 and 5 move up in the jack-up direction. As a result, the receiving portion 11 can be applied to the side sill on the vehicle body side.

If the male threadless portion 77 is provided only on the tip side of the male threaded portion 75 as described above, the upward movement of the receiving portion 11 by the urging force of the torque springs 45 and 47 is restricted. It is also possible to make it face the side sills on the vehicle body side with a slight gap.

As described above, in the unloaded state, the screwing of the male screw portion 75 with the movable female screw portion 57 and the female screw portion 65 is released to rotate the screw shaft 25 without rotating the receiving portion 1.
You can raise 1. Therefore, even if the screw pitch of the screw shaft 25 is reduced in order to reduce the operating force when a load is applied, it does not affect the operation under no load and the operation is extremely simple. .

The operation without load is from the state where the male screw portion 75 and the movable female screw portion 57 and the female screw portion 65 are screwed in the retracted state, but the screwing is released in the retracted state. In this case, the worker should take out the upper and lower arms 7, 9, 3, 5 from the bracket of the vehicle body while folding them against the urging force of the torque springs 45, 47, place them under the vehicle body, and let go. As a result, the receiving portion 11 can be immediately moved upward, brought into contact with the side sill on the vehicle body side, or arranged in the vicinity thereof.

(At the time of jacking up) In order to jack up the receiving portion 11 against the side sill on the vehicle body side or facing each other with a slight gap, first, the movable screw member 49 is operated to make the male screw portion 75 and the movable female screw portion 57. And, the screw engagement with the female screw portion 65 is connected. That is, in the above state, the fixing pin 73 is pulled out from the locking hole 71, and the handle 53
Is operated to rotate the tubular portion 53 in the support hole 69 by approximately 90 °. By this rotation, the movable female screw portion 57 and the female screw portion 6
5 is as shown in FIG. 6B when viewed from the axial direction. That is, the movable female screw portion 57 of the movable screw member 49 is
The female screwless portion 67 and the female screwless portion 59 are opposed to each other. Therefore, when viewed from the axial direction, the internal thread portion is present as a whole. In this state, the fixing pin 73 is inserted into the locking hole 71 and engaged with the fixing pin groove 63 in the support hole 69. As a result, in the state of FIG. 6B, the cylindrical portion 53 is restricted from rotating with respect to the support hole 69 and is prevented from coming off.

Then, when the screw shaft 25 is rotated by the jack handle, the male screw portion 75 is screwed with the movable female screw portion 57, the female screw portion 65, or both at the same time as the male screw portion 75 is rotated. The screwed state can be maintained. As a result, the upper and lower arms 7, 9,
3 and 5 can be raised in the jack-up direction,
The vehicle body can be lifted via the receiving portion 11. In this case, the male screw portion 75, the movable female screw portion 57, and the female screw portion 65.
If the screw pitch is small, the increase in the operating force at the time of jacking up is small, and the operating force can be significantly improved by reducing the operating force.

(During storage) The screw shaft 25 is rotated in the opposite direction to lower the upper and lower arms 7, 9, 3, 5 so that no load is applied. To change from this state to the retracted state, the upper and lower arms 7,
We have to fold 9, 3, 5 further. In this case, the movable screw member 49 is rotated by the opposite operation to the above, and is fixed by the fixing pin 73.
The screwing of 5 with the movable female screw portion 57 and the female screw portion 65 is released. When the receiving portion 11 is further pushed down by the pushing force of the hand or the like by this release, the pantograph jack can be easily detached from the bottom of the vehicle body and can be stored in the storage portion of the vehicle body. When stored in the vehicle body, the urging force of the torque springs 45, 47 causes the base 1 and the receiving portion 11 to be stretched against the support bracket on the vehicle body side, and can be securely fixed. If the movable screw member 49 is rotated again in the retracted state to connect the male screw portion to the movable female screw portion 57 and the female screw portion 65, the rotation of the screw shaft 25 causes the base 1 and the receiving portion 11 to move to the vehicle body side. It can be stretched against the bracket and can be securely fixed in the stored state.

The present invention is not limited to the above embodiment. Fixing pin grooves 61, 6 of the fixing means 51
3 can also be a hole. Further, the cylindrical portion 53 has an outer periphery formed in, for example, a quadrangle, and the supporting hole 69 is also formed in a four-section cross-section correspondingly. It is possible to perform the same operation as above. Also, the support hole 6
The fixing structure of the movable screw member 49 with respect to 9 may also be configured by, for example, projecting a rounded pin urged by a coil spring toward the support hole side and forming a concave portion engaging with the pin on the cylindrical portion 53 side. it can. In this case, the tubular portion 53 is attached to the support hole 6
When inserted in 9, the pin is pulled back against the spring due to the roundness of the tip of the pin which is biased by the coil spring, and the pin is projected again at a position facing the recess of the cylindrical portion 53 and engaged with the recess. Therefore, the operation of inserting and removing the pin becomes unnecessary, and the operation becomes easier. It is also possible to engage and disengage from the recess of the movable screw member by operating the pin biased by such a spring from the outside.

[0045]

As is clear from the above, according to the first aspect of the invention, when no load is applied, the screw engagement / disconnection mechanism releases the screw engagement between the male screw portion of the screw shaft and the female screw portion side of the connecting member. The receiving part can be raised and lowered without operating the shaft. Therefore, the operation under no load is facilitated and the operability can be remarkably improved. or,
Since the operation of the screw shaft is not involved when there is no load, the screw pitch of the screw shaft can be reduced to reduce the operating force.
From this point as well, the operability is remarkably improved.

According to the second aspect of the invention, in addition to the effect of the first aspect of the invention, the male screw portion is axially opposed to the female screwless portion of the connecting member and the female screwless portion of the movable screw member, whereby the screwing is easily released. can do. Further, in this state, the movable screw member can be fixed by the fixing means. Therefore, the unscrewing of the male screw portion can be reliably and easily performed.

According to the invention of claim 3, in addition to the effect of the invention of claim 2, the tubular portion of the movable screw member can be rotated with respect to the support hole by operating the handle, and the operation of the movable screw member is extremely easy. Becomes Therefore, the operability is significantly improved.

According to the invention of claim 4, in addition to the effect of the invention of claim 3, the tubular portion can be fixed or rotated by the engagement / disengagement of the locking member with respect to the engaging portion, and the movable screw member can be fixed. The rotation can be performed easily and surely.

According to the invention of claim 5, in addition to the effect of the invention of claim 4, the fixing pin can be engaged with and disengaged from the fixing pin groove of the movable screw member by inserting / removing the fixing pin into / from the locking hole of the connecting member. . Therefore, the movable screw member can be fixed and rotated easily and surely.

According to the invention of claim 6, in addition to the effects of the inventions of claims 2-5, by forming the female screwless portion by approximately 90 ° and by forming the male screwless portion in a wider range than approximately 90 °. The screwing of the male screw portion to the female screwless portion can be reliably performed.

[Brief description of drawings]

FIG. 1 is a side view of a pantograph jack according to an embodiment of the present invention.

FIG. 2 is a partially cutaway perspective view of a main part according to an embodiment.

FIG. 3 is a sectional view of a connecting shaft at a fixing pin position.

FIG. 4 is a sectional view taken along line IV-IV of FIG. 3;

5A and 5B show a part without a female screw, FIG. 5A is a cross-sectional view of a connecting shaft side, and FIG. 5B is a cross-sectional view of a movable screw member side.

FIG. 6 is an operation explanatory view, (a) shows a state when the screwing is released,
(B) is a cross-sectional view at the time of screw connection.

FIG. 7 is a perspective view of a pantograph jack according to a conventional example.

8A and 8B are cross-sectional views of a main part according to another conventional example, in which FIG. 8A is a cross-sectional view when screwing is released, and FIG.

[Explanation of symbols]

 1 Base 3,5 Lower Arm 7,9 Upper Arm 11 Receiving Part 17,19 Connecting Shaft (Connecting Member) 25 Screw Shaft 43 Threading Intermittent Mechanism 45,47 Torque Spring (Biasing Member) 49 Movable Screw Member 51 Fixing Means 53 Cylindrical part 55 Handle 57 Movable female screw part 59 No female screw part 61, 63 Fixing pin groove 65 Female screw part 67 No female screw part 69 Support hole 71 Locking hole 73 Fixing pin 75 Male screw part 77 No male screw part

Claims (6)

[Claims] 1. A pair of lower arms whose lower ends are rotatably supported by a base and upper ends of the lower arms, one of which is a female screw part and the other of which the lower ends are connected through a pair of connecting members having through holes. A pair of upper arms, which are rotatably supported and whose upper ends are directly or indirectly rotatably supported, and each of which has a receiving portion for receiving a jack-up counterpart on the upper end side, and a female screw portion of the one connecting member. And a screw shaft provided with a rotation operating part that is rotatably supported in a through hole of the other connecting member and is immovable in the axial direction, and the female screw part of the one connecting member and the screw shaft. The pantograph jack is characterized in that a screwing connecting / disconnecting mechanism capable of releasing mutual screwing and connecting and operating is provided between the male screw part and the male screw part, and an urging member for urging the upper and lower arms upward. 2. The pantograph jack according to claim 1, wherein the screw engagement / disconnection mechanism is provided concentrically with the female screw portion of the one connecting member, and is rotatable about the axis with respect to the connecting member. Together with a movable screw member that can be fixed by a fixing means and has a movable female screw portion in the shaft center portion, and at least a pair of male screw-free portions that are provided at symmetrical positions on the outer periphery of the male screw portion with the shaft center interposed therebetween, and At least a pair of female screw-free portions are provided at symmetrical positions on the inner circumferences of the female screw portion and the movable female screw portion so as to leave a part of the female screw portion and the movable female screw portion corresponding to the male screw-less portion. A pantograph jack that is characterized. 3. The pantograph jack according to claim 2, wherein the movable screw member has a cylindrical outer periphery and a cylindrical portion having the movable female screw portion concentrically, and one end portion of the cylindrical portion. And a support hole provided concentrically with the female screw portion for rotatably fitting the tubular portion of the movable screw member. And a pantograph jack. 4. The pantograph jack according to claim 3, wherein the fixing means includes a releasable locking member provided on the one coupling member side, the movable female screw portion and the female screw provided on the tubular portion. A pantograph jack comprising at least a pair of engaging portions respectively corresponding to a non-existing portion. 5. The pantograph jack according to claim 4, wherein the locking member is a fixing pin that is removably inserted into a locking hole that penetrates from the outer surface of the connecting member to the support hole, The pantograph jack, wherein the engaging portion is a fixing pin groove provided on the outer peripheral surface of the cylindrical portion of the movable screw member and engaging with the fixing pin. 6. The pantograph jack according to claim 2, wherein the female screwless portion is provided within a range of about 90 ° of the inner circumference, and the male screwless portion is about 90 ° of the outer circumference. The pantograph jack is characterized in that it is provided in a wider range than the distribution.