JP6587393B2 - Screw jack - Google Patents

Description

  The present invention mainly relates to a three-stage screw jack that is installed in large automobiles, buses, trucks, and the like and is used to lift a vehicle when changing tires.

  As a screw jack, for example, a case protruding on a base, an outer cylinder (ram guide) that is slidably fitted in the axial direction inside the case, and an up-and-down direction inside the outer cylinder A three-stage screw jack having an inner cylinder (ram) that is slidably fitted is known (see, for example, Patent Document 1).

  When this three-stage screw jack is used, for example, when a part of an automobile or the like is loaded on a vehicle receiving portion rotatably fitted to the upper end of a ram (inner cylinder) and the handle is rotated, The bevel gear and the large bevel gear are rotated, the main screw shaft is rotated to raise the auxiliary screw cylinder, and the inner cylinder screwed with the auxiliary screw cylinder is raised.

  When the inner cylinder (ram) rises, the outer cylinder (ram guide) is also pulled up by the inner cylinder, and the automobile or the like is lifted via a vehicle receiving portion provided at the upper end of the inner cylinder (ram).

Registered Utility Model No. 3046162

  However, in the conventional screw jack described in Patent Document 1, a vehicle receiving portion is rotatably attached to the upper end of the inner cylinder by a bolt, a screw, or the like when an automobile or the like to be lifted is placed. There is a problem that it takes time to mount the receiving portion, and that the receiving portion such as the vehicle may fall off from the upper end portion of the inner cylinder when receiving vibration for a long time when mounted on the vehicle.

  Therefore, the present invention has been made paying attention to such problems, and is easy to attach to the upper end of the inner cylinder, and even if the vehicle is vibrated for a long time when mounted on the vehicle, etc. It is an object of the present invention to provide a screw jack in which the receiving part is not likely to fall off from the upper end part of the inner cylinder.

In order to solve the above-mentioned problems, a screw jack according to the present invention has a case mounted on a bed provided with a thrust bearing at the center, and a screw is formed on the outer peripheral surface of the thrust bearing, and a stopper pin is provided at an upper end portion. A large bevel gear with a main screw shaft provided upright is provided, and the large bevel gear meshes with a small bevel gear that rotates by driving from the outside of the case, while the main screw that rotates via the large bevel gear Auxiliary screw outer periphery provided on the outer peripheral surface of the auxiliary screw cylinder is engaged with an outer peripheral screw portion provided on the inner surface of the lower portion of the auxiliary screw cylinder while the outer peripheral screw portion provided on the outer peripheral surface of the shaft is engaged The screw portion meshes with an inner cylinder inner peripheral screw portion provided on the inner peripheral surface of the inner cylinder lower portion, and the large bevel gear and the main screw shaft are rotated by the rotation of the small bevel gear, and the main screw shaft The auxiliary screw cylinder moves up and down by the rotation of the The inner cylinder is raised and lowered by the rotation of the auxiliary screw cylinder, and the inner cylinder side stopper provided on the outer peripheral surface of the lower part of the inner cylinder contacts the outer cylinder side stopper provided on the inner peripheral surface of the upper part of the outer cylinder. The outer cylinder is also raised, and a screw jack provided with a vehicle receiving portion for receiving a vehicle or the like at the upper part of the inner cylinder, and the outer peripheral surface of the upper part of the inner cylinder has a circular shape at a predetermined interval. 6 is an approximate hexagonal shape in plan view with six long curved side surfaces provided alternately with six long flat side surfaces and long curved side surfaces cut by six straight lines. The side surface is a portion recessed from the outer peripheral surface of the inner cylinder side stopper portion, and the upper portion of the outer peripheral surface of the inner cylinder is a circle having a radius from the center of the long flat side surface to the center of the inner cylinder in plan view. A C-ring receiving groove having a circumference is provided, and the C-ring receiving groove While C-ring having elasticity is fitted into,
The vehicle or the like receiving portion has an inverted cup shape having a circular upper surface and a cylindrical side surface covering the upper end portion of the inner cylinder, and a C ring fitting groove portion into which the C ring fits on the inner side surface of the cylindrical side surface Is provided,
By covering the vehicle receiving part on the upper part of the vehicle receiving part in which the C ring is accommodated in the C ring fitting groove, and fitting the C ring into the C ring fitting groove of the vehicle receiving part The vehicle receiving portion is rotatably attached to an upper portion of the inner cylinder.

In the screw jack of the present invention, the upper part of the outer peripheral surface of the inner cylinder is provided with a C-ring housing groove for housing an elastic C-ring, and the C-ring is fitted into and accommodated in the C-ring housing groove. On the other hand, the vehicle receiving portion has an inverted cup shape having a circular upper surface and a cylindrical side surface covering the upper end portion of the inner cylinder, and a C ring fitting groove portion into which the C ring fits on the inner side surface of the vehicle receiving portion. The vehicle ring receiving portion is placed on the upper portion of the vehicle receiving portion in which the C ring is accommodated in the C ring fitting groove portion, and the C ring is fitted into the C ring fitting groove portion of the vehicle receiving portion. Thus, the vehicle receiving portion was rotatably attached to the upper portion of the inner cylinder.
For this reason, the vehicle receiving portion can be easily attached to the upper end of the inner cylinder, and even if the vehicle receiving portion receives vibration for a long time when mounted on the vehicle, the vehicle receiving portion is supported by an elastic C-ring. Since it fits in the C-ring fitting groove on the upper part of the outer peripheral surface of the inner cylinder, it is possible to reliably prevent the receiving part such as the vehicle from dropping off from the upper end of the inner cylinder.

It is sectional drawing which shows the cross-sectional structure of the contracted state (accommodated state) which is not using the screw jack of Embodiment 1 which concerns on this invention. It is an end view which shows the AA line cross section in FIG. It is a top view of the screw jack of Embodiment 1 which concerns on this invention. It is a perspective view of the inner cylinder which comprises the screw jack of Embodiment 1 which concerns on this invention. It is the top view, front view, and side view of an inner cylinder which comprise the screw jack of Embodiment 1 which concerns on this invention, respectively. (A), (b) is the BB sectional drawing and CC sectional drawing in FIG.5 (b), respectively. It is a perspective view of the outer cylinder which comprises the screw jack of Embodiment 1 which concerns on this invention. (A)-(c) It is a top view, a front view, and a left view of the outer cylinder which comprises the screw jack of Embodiment 1 which concerns on this invention, respectively. (A), (b) is the DD sectional view taken on the line in FIG.8 (c), respectively, and the EE sectional view taken on the line in FIG.8 (b). (A)-(e) It is sectional drawing which shows the process in which C ring and a receiving part, such as a vehicle, are mounted | worn in the inner cylinder which comprises the screw jack of Embodiment 1 which concerns on this invention, respectively. (A)-(e) It is a top view corresponding to FIG.10 (a)-(e), respectively, or a partially notched cross-sectional view. FIG. 3 is a front cross-sectional view showing a cross-sectional structure when the outer cylinder and the auxiliary screw cylinder, which are the second stage of the screw jack according to the first embodiment of the present invention, extend upward as much as possible from the first stage cylindrical case part. is there. Left side sectional view showing a sectional structure when the outer cylinder and the auxiliary screw cylinder which are the second stage of the screw jack according to the first embodiment of the present invention are fully extended upward from the first stage cylindrical case portion. It is. FIG. 14 is an end view taken along line FF in FIG. 13. The front view which shows the state which the inner cylinder which is the 3rd step | paragraph of the screw jack of Embodiment 1 which concerns on this invention, the outer cylinder which is the 2nd step | paragraph, etc. extended all the way up from the 1st step | paragraph cylindrical case part. It is. The left side surface which shows the state which the inner cylinder which is the 3rd step of the screw jack of Embodiment 1 which concerns on this invention, the outer cylinder which is the 2nd step, etc. has extended from the 1st step cylindrical case part to the maximum. FIG. The cross-sectional structure when the inner cylinder, which is the third stage, the outer cylinder, which is the second stage, and the like of the screw jack according to the first embodiment of the present invention is fully extended upward from the cylindrical case part of the first stage. It is front sectional drawing shown. It is the GG line | wire end view in FIG.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a screw jack according to the present invention will be described in detail with reference to the accompanying drawings.

Embodiment 1 FIG.
As shown in FIGS. 1-3, the screw jack 1 of Embodiment 1 which concerns on this invention is comprised by attaching the case 13 on the bed 12 which provided the thrust bearing 11 in the center.

  The case 13 has a case main body 13a fixed on the bed 12 in a shape like a bowl fixed on the bed 12 by bolts and nuts (not shown), and extends vertically from the upper portion of the case main body 13a. The first-stage cylindrical case portion 13b having a predetermined length, and a handle joint support cylindrical portion 13c into which a handle joint 17 described later is inserted and rotatably support the handle joint 17 are configured.

  In the case main body 13a, a large bevel gear 14 is rotatably provided on the thrust bearing 11, and a central screw outer peripheral thread portion extending from the lower end to the upper end on the outer peripheral surface is provided at the center of the large bevel gear 14. 15a is formed, a stopper pin 16 is provided at the upper end, and a main screw shaft 15 is erected.

  The large bevel gear 14 meshes with a small bevel gear 18 provided at a tip end portion of a handle joint 17 rotatably supported by the handle joint support cylindrical portion 13c, and when the handle joint 17 is rotated, the small bevel gear 18 is rotated. Is rotated so that the large bevel gear 14 is also rotated. In addition, an insertion hole 17 a into which a screwdriver or a dedicated rod is inserted to rotate the handle joint 17 is provided at the rear end portion of the handle joint 17.

  The main screw outer peripheral screw portion 15a provided on the outer peripheral surface of the main screw shaft 15 is engaged with the auxiliary screw inner peripheral screw portion 19a provided on the inner surface of the lower portion of the auxiliary screw cylinder 19, while The auxiliary screw outer peripheral screw portion 19b provided on the surface meshes with the inner cylinder inner peripheral screw portion 20a provided on the inner peripheral surface of the lower portion of the inner cylinder 20.

  Here, the main screw shaft 15 and the auxiliary screw cylinder 19 reduce the frictional resistance of the threaded portion by the gas soft nitriding treatment, thereby making it resistant to wear and improving the durability performance. The gas soft nitriding treatment increases the hardness of the load receiving surface of the threaded portion by precipitating a compound layer on the surface, thereby improving the wear resistance.

  Further, the material of the main screw shaft 15 and the auxiliary screw cylinder 19 is FCD400 (spheroidal graphite cast iron), so that the toughness is improved and the fracture resistance against lateral load is improved.

  This is a safety risk because FC200 (gray cast iron) is a fracture mode that breaks when a transverse fold test is performed on a brittle material peculiar to castings. For this reason, steel may be used for the main screw shaft 15 and the auxiliary screw cylinder 19 to take measures against this damage mode. However, steel is too viscous to deteriorate the machinability and reduce the mass productivity in machining. In addition, when steel is used, a technique called plastic working (rolling) is used to solve the problem, but this requires a large amount of capital investment and costs. The toughness of FCD400 (spheroidal graphite cast iron) is a material having intermediate toughness between FC200 (grey cast iron) and steel, and is a material that can be cut relatively easily. It was used as a material for the screw shaft 15 and the auxiliary screw cylinder 19.

  As shown in FIG. 1 and the like, the cylindrical case portion 13b has a predetermined length of steel pipe that houses the main screw shaft 15, the auxiliary screw cylinder 19, the inner cylinder 20, and the outer cylinder 21 when the screw jack 1 is not used. As shown in FIG. 2 and the like, the main guide groove portion 13b1 extending in the vertical direction for guiding the guide portion 21a of the outer cylinder 21 described later in the vertical direction and the side facing the main guide groove portion 13b1, that is, On the opposite side of 180 degrees, there is a sub guide groove 13b2 extending in the vertical direction that guides the retaining projection 21b of the outer cylinder 21 in the vertical direction.

  When the outer cylinder 21 rises, the retaining guide 21b of the outer cylinder 21 comes into contact with the upper portion of the sub guide groove 13b2 so that the outer cylinder 21 does not fall out of the cylindrical case 13b (center side). ) Is provided with a cylindrical case-side stopper portion 13b3 (see FIG. 12 and the like) that is bent toward the top.

  Further, the inner cylinder side stopper portion 20b provided on the outer peripheral surface side of the lower portion of the inner cylinder 20 abuts on the outer cylinder side stopper portion 21c provided on the inner peripheral surface side of the upper portion of the outer cylinder 21, so The cylinder 21 is also configured to be raised.

  That is, in the screw jack 1, the large bevel gear 14 and the main screw shaft 15 are rotated by the rotation of the handle joint 17 and the small bevel gear 18, and the auxiliary screw cylinder 19 is moved up and down by the rotation of the main screw shaft 15, while the auxiliary screw When the inner cylinder 20 is moved up and down by the rotation of the cylinder 19, the inner cylinder side stopper portion 20 b provided on the outer peripheral surface side of the lower portion of the inner cylinder 20 is changed to the outer cylinder side stopper portion 21 c provided on the inner peripheral surface side of the upper portion of the outer cylinder 21. The outer cylinder 21 is also lifted by contact.

  A vehicle receiving portion 22 that receives the load of a vehicle such as a large automobile, a bus, or a truck is attached to the upper portion of the inner cylinder 20.

<Configuration of inner cylinder 20>
4 is a perspective view showing the outer appearance of the inner cylinder 20 constituting the screw jack 1 of Embodiment 1, and FIGS. 5A to 5C are a plan view, a front view, a right side view, and a right side view, respectively. FIGS. 6A and 6B are a cross-sectional view taken along line BB and a cross-sectional view taken along line CC in FIGS. 5B and 5C, respectively.

  The inner cylinder 20 is not made of steel (steel material), but is made of FCD400 (spherical graphite cast iron) that has been subjected to gas soft nitriding in the same manner as the main screw shaft 15 and the auxiliary screw cylinder 19. The inner cylinder inner peripheral thread portion 20a is provided on the side, while the inner cylinder 20 has a circular cut surface when the inner cylinder 20 is cut in a horizontal direction perpendicular to the longitudinal direction below the outer surface. A side stopper portion 20b is provided.

  As shown in FIGS. 4 to 6 and the like, the outer surface of the inner cylinder 20 other than the lower inner cylinder side stopper portion 20b has six outer circumferential surfaces of the inner cylinder 20 at predetermined intervals. The inner cylinder slide portion 20c in which the six long flat side surfaces 20c1 and the curved side surfaces 20c2 are alternately arranged is formed by cutting in a plane, and the inner cylinder slide portion 20c is in a horizontal direction perpendicular to the longitudinal direction. The cut surface shape at the time of cutting into six is the six long curved side surfaces 20c2 provided alternately with the six long flat side surfaces 20c1 and the long curved side surfaces 20c2 by cutting off a circular shape by six straight lines at predetermined intervals. It is an approximate hexagon as a corner, and the long flat side surface 20c1 at that portion is a portion recessed from the outer peripheral surface of the inner cylinder side stopper portion 20b.

  Therefore, in the inner cylinder 20, the long curved side surface 20c2 of the inner cylinder slide portion 20c and the surface of the inner cylinder side stopper portion 20b are continuously flush with each other as shown in FIGS. The long flat side surface 20c1 of the inner cylinder slide portion 20c and the inner cylinder side stopper portion 20b have a step, and the long flat side surface 20c1 of the inner cylinder slide portion 20c is recessed inward from the inner cylinder side stopper portion 20b. It will be.

  As shown in FIG. 10 (a), the upper part of the outer surface of the inner cylinder 20, that is, the upper part of the outer surface of the inner cylinder slide part 20c, has a C-ring fitting groove 22c inside the vehicle receiving part 22 described later. A C-ring housing groove 20d for housing the C-ring 23 that fits in is formed, and as shown in FIG. 10B, the C-ring housing groove 20d accommodates the elastic C-ring 23. .

<Configuration of outer cylinder 21>
7 is a perspective view showing an outer appearance of the outer cylinder 21 constituting the screw jack 1 of the first embodiment, and FIGS. 8A to 8C are a front view, a right side view, and a plan view of the outer cylinder 21, respectively. 9A and 9B are a cross-sectional view taken along the line BB and a cross-sectional view taken along the line CC in FIGS. 8B and 8C, respectively.

  The outer cylinder 21 is made of a steel pipe, and as shown in FIGS. 7 to 9, the inner cylinder 20 has an inner diameter corresponding to the circular shape of the cut surface of the inner cylinder side stopper portion 20b so that it can be stored when the inner cylinder 20 is lowered. The outer peripheral surface of the guide portion 21a protrudes from the inner side to the outer side with a predetermined width from the upper end portion to the lower end portion, and is guided by a main guide groove portion 13b1 of a case body portion 13b of the case 13 described later. Is provided.

  Further, on the opposite side of the outer peripheral surface of the outer cylinder 21 from the lower portion of the guide portion 21a, as shown in FIGS. 7 to 9, the outer cylinder 21 is outside from the inside so as not to come out of the case main body portion 13a of the case 13. A retaining protrusion 21b that protrudes toward the surface is provided.

  Further, as shown in FIGS. 7 to 9, only the upper portion of the outer cylinder 21, only the cut surface shape of the inner cylinder side slide portion 20c of the inner cylinder 20, that is, the outer shapes of the six long flat side surfaces 20c1 and the long curved side surface 20c2. The outer cylinder side stopper part 21c which has the shape crushed toward the inner side from the outer side is provided so that it may become the approximate hexagon which a line draws.

  The outer cylinder-side stopper portion 21c at the top of the outer cylinder 21 has six short flat side surfaces 21c1 and a long curved side surface by linearly crushing the upper end portion of the cylindrical outer cylinder 20 at six locations at predetermined intervals from the outside to the inside. 21c2 and the alternating shape are formed.

<Configuration of the vehicle receiving portion 22 and mounting to the inner cylinder 20>
As shown in FIG. 10C, the vehicle receiving portion 22 has an inverted cup shape having a circular upper surface 22a that covers the upper end portion of the inner cylinder 20, and a cylindrical cylindrical side surface 22b. A C-ring fitting groove 22C into which the C-ring is fitted is provided on the inner side surface of the cylindrical side surface 22b of the vehicle receiving portion 22.

  Since the C-ring housing groove 20d at the upper part of the outer surface of the inner cylinder 20 is mounted and accommodated with an elastic C-ring 23 as shown in FIGS. 10A and 10B, FIG. When the vehicle etc. receiving part 22 is put on the upper end part of the inner cylinder 20 as shown in c), the C ring 23 is bent by the inner side surface of the cylindrical side 22b of the vehicle etc. receiving part 22 as shown in FIG. Finally, as shown in FIG. 10 (e), the C ring 23 housed in the C ring housing groove portion 20 d of the inner cylinder 20 is fitted into the C ring fitting groove portion 22 c of the vehicle receiving portion 22.

  FIGS. 11A to 11E are plan views or partially cutaway cross-sectional views showing the states of FIGS. 10A to 10E, respectively. That is, FIG. 11A is a plan view showing the state of FIG. 10A before the C-ring 23 is accommodated in the C-ring accommodating groove 20d on the outer side surface of the inner cylinder 20, and FIG. FIG. 10B shows the state of FIG. 10B in which the C ring 23 is expanded to accommodate the C ring 23 in the C ring accommodating groove 20d of the inner cylinder 20, and FIG. It is a top view which shows the state of FIG.10 (c) in which C ring 23 was accommodated. 11D shows a state before the vehicle receiving portion 22 is inserted into the upper end portion of the inner cylinder 20 and the C ring 23 is fitted into the C ring fitting groove 22c of the vehicle receiving portion 22, FIG. e) is a plan view showing a state in which the C-ring 23 is fitted into the C-ring fitting groove 22c of the vehicle receiving portion 22 and is attached to the vehicle receiving portion 22 at the upper end of the vehicle receiving portion 22;

  In addition, the circular upper surface 22a of the vehicle receiving portion 22 is formed with a cross-shaped vehicle receiving groove 22a1 that is in contact with the lower portion of the vehicle or the like as shown in FIG. . The vehicle groove 22a1 may have a negative shape.

  Next, the operation and effect of the screw jack 1 of the present embodiment configured as described above will be described.

  First, as shown in FIG. 1, when an insertion hole 17a driver or a dedicated rod of the handle joint 17 is inserted and rotated, the handle joint 17 and the small bevel gear 18 provided at the tip end thereof are rotated. The large bevel gear 14 meshing with the gear 18 rotates.

  Then, the main screw shaft 15 having its lower end fixed to the large bevel gear 14 is rotated by the rotation of the large bevel gear 14, and the main screw outer peripheral screw provided on the outer peripheral surface of the main screw shaft 15 as shown in FIG. The auxiliary screw cylinder 19 with the portion 15a meshing with the auxiliary screw inner peripheral screw portion 19a is raised.

  10 to 12, the upper portion of the auxiliary screw inner peripheral screw portion 19 a provided on the inner surface of the lower portion of the auxiliary screw tube 19 is formed on the outer peripheral surface of the main screw shaft 15. When abutting against the stopper pin 16 embedded in the upper portion of the provided main screw outer peripheral thread portion 15 a, the auxiliary screw cylinder 19 is fixed to the main screw shaft 15, and the auxiliary screw cylinder 19 is also rotated by the rotation of the main screw shaft 15. become.

  When the auxiliary screw cylinder 19 rotates, the auxiliary screw outer peripheral screw part 19b provided on the outer peripheral surface of the auxiliary screw cylinder 19 and the inner cylinder inner peripheral screw part 20a provided on the inner peripheral surface of the lower part of the inner cylinder 20 mesh with each other. Therefore, the inner cylinder 20 is raised.

  When the inner cylinder 20 is raised by the rotation of the auxiliary screw cylinder 19, an inner cylinder-side stopper portion 20 b is provided at the lower portion of the outer surface of the inner cylinder 20, and the inner cylinder-side stopper portion 20 b serves as the outer cylinder 21. When it comes into contact with the upper outer cylinder side stopper portion 21c, the outer cylinder 21 is raised together with the inner cylinder 20.

  When the outer cylinder 21 rises together with the inner cylinder 20, the vehicle receiving portion 22 attached to the upper end portion of the inner cylinder 20 comes into contact with the lower part of the vehicle (not shown) to lift the vehicle. At that time, since the vehicle receiving portion 22 is rotatably attached to the upper end portion of the inner cylinder 20 by the C ring 23, the vehicle receiving groove 22a1 provided on the circular upper surface 22a of the vehicle receiving portion 22 is formed at the lower portion of the vehicle. When abutting, the receiving portion 22 such as the vehicle can be rotated and easily abutted.

  Then, the outer cylinder 21 rises together with the inner cylinder 20, and the guide portion 21a and the retaining projection 21b of the outer cylinder 21 are guided to the main guide groove portion 13b1 and the sub guide groove portion 13b2 of the cylindrical case portion 13b, respectively. When the outer cylinder 21 as well as the inner cylinder 20 rises from the cylindrical case portion 13b of the case 13, the retaining projection 21b of the outer cylinder 21 eventually becomes the sub guide groove portion of the cylindrical case portion 13b. As shown in FIGS. 13 to 16, the ascending of the inner cylinder 20 and the outer cylinder 21 is stopped by coming into contact with the cylindrical case side stopper 13 b 3 at the upper part of 13 b 2.

  Therefore, according to the screw jack 1 of the present embodiment, the C-ring housing groove 20d for housing the C-ring 23 is provided on the upper portion of the inner cylinder 20, and the C-ring 23 is fitted into the C-ring housing groove 20d. On the other hand, the vehicle receiving portion 22 has an inverted cup shape having a circular upper surface and a cylindrical side surface covering the upper end portion of the inner cylinder 20, and a C ring is provided on the inner side surface of the vehicle receiving portion 22. A C-ring fitting groove 22 </ b> C into which the vehicle 23 is fitted is provided. The vehicle receiving part 22 is covered on the upper part of the vehicle receiving part 22, and the C ring 23 is fitted into the C-ring fitting groove 22 c of the vehicle receiving part 22. Accordingly, the vehicle receiving portion 22 is configured to be rotatably attached to the upper portion of the inner cylinder 20, so that the attachment of the vehicle receiving portion 22 to the upper end portion of the inner cylinder 20 is facilitated.

  Moreover, in the screw jack 1 of this embodiment, since the attachment part 22 of the vehicle etc. to the inner cylinder 20 is using the C ring 23 which is a spring which has elasticity, in the state which mounted this screw jack 1 on the vehicle. Even when the vehicle travels for a long time and receives vibration for a long time, the vehicle receiving portion 22 is fitted into the C ring fitting groove portion 22c on the outer peripheral surface of the inner cylinder 20 by the elastic C ring 23. Therefore, it is possible to reliably prevent the vehicle receiving portion 22 from dropping from the upper end portion of the inner cylinder 20.

  Moreover, in the screw jack 1 of this embodiment, the shape of the outer peripheral surface of the upper part of the inner cylinder 20 is provided with six straight portions and six curved curved corners alternately at predetermined intervals, and six curved angles. Although it is an approximate hexagon having a corner portion and is not circular, since the vehicle receiving portion 22 is mounted on the upper portion of the inner cylinder 20 by the C ring 23, the vehicle receiving portion 22 is prevented from coming off at the upper portion of the inner cylinder 20. It becomes possible to rotate smoothly in the state where it was done, and jack-up operation can be performed smoothly.

  In the screw jack 1 of the above embodiment, the outer surface of the inner cylinder slide portion 20c other than the lower inner cylinder side stopper portion 20b on the outer surface of the inner cylinder 20 is a cylinder as shown in FIGS. The outer peripheral surface of the inner cylinder 20 having a shape was cut into six planes at a predetermined interval, and formed into an approximate hexagonal shape in which six long flat side surfaces 20c1 and curved side surfaces 20c2 are alternately arranged. However, the present invention is not limited to this, and it is of course possible to form four or five points at a predetermined interval with a flat surface, or a polygonal shape with seven or eight or more points. In this case, the shape of the outer cylinder side stopper portion 21c above the outer cylinder 21 is also a polygon corresponding to the outer shape of the inner cylinder slide portion 20c of the inner cylinder 20.

DESCRIPTION OF SYMBOLS 1 Screw jack 11 Thrust bearing 12 Bed 13 Case 13a Case main-body part 13b Cylindrical case part 13b1 Main guide groove part 13b2 Sub guide groove part 13c Handle joint support cylindrical part 14 Large bevel gear 15 Main screw shaft 15a Main screw outer periphery screw part 15a
16 Stopper pin 17 Handle joint 18 Small bevel gear 19 Auxiliary screw cylinder 19
19a Auxiliary screw inner peripheral screw part 19b Auxiliary screw outer peripheral screw part 20 Inner cylinder 20a Inner cylinder inner peripheral screw part 20b Inner cylinder side stopper part 20c Inner cylinder slide part 20d C ring accommodating groove part 21 Outer cylinder 21a Guide part 21b Retaining protrusion 22 Vehicle Receiving Portion 22a Circular Top 22a1 Vehicle Receiving Groove 22b Cylindrical Side 22c C Ring Fitting Groove 23 C Ring

Claims (1)

A case is mounted on a bed provided with a thrust bearing in the center, a screw is formed on the outer peripheral surface of the thrust bearing, and a large bevel gear with a main screw shaft provided with a stopper pin at the upper end is made upright. The large bevel gear is meshed with a small bevel gear that rotates by driving from the outside of the case, while the main screw outer peripheral thread portion provided on the outer peripheral surface of the main screw shaft that rotates through the large bevel gear is provided. Is engaged with the inner screw portion of the auxiliary screw provided on the inner surface of the lower portion of the auxiliary screw cylinder, while the outer screw portion of the auxiliary screw provided on the outer peripheral surface of the auxiliary screw tube is provided on the inner peripheral surface of the lower portion of the inner cylinder. The inner cylinder inner peripheral screw part is meshed,
The rotation of the small bevel gear rotates the large bevel gear and the main screw shaft, and the rotation of the main screw shaft raises and lowers the auxiliary screw tube, while the rotation of the auxiliary screw tube raises and lowers the inner tube. The outer cylinder is also raised by the inner cylinder stopper provided on the outer peripheral surface of the lower part of the inner cylinder abutting the stopper on the outer cylinder provided on the inner peripheral surface of the upper part of the outer cylinder. A screw jack provided with a receiving portion for receiving a vehicle or the like at the top,
The shape of the outer peripheral surface of the upper part of the inner cylinder is a corner of six long curved side surfaces provided alternately with six long flat side surfaces and long curved side surfaces by cutting off a circular shape by six straight lines at predetermined intervals. A plan view, an approximate hexagon, and the elongated flat side surface is a portion recessed from the outer peripheral surface of the inner cylinder side stopper portion;
An upper portion of the outer peripheral surface of the inner cylinder is provided with a C-ring receiving groove having a circumference with a radius from the center of the long flat side surface to the center of the inner cylinder in plan view. While the elastic C ring is fitted in the groove ,
The vehicle or the like receiving portion has an inverted cup shape having a circular upper surface and a cylindrical side surface covering the upper end portion of the inner cylinder, and a C ring fitting groove portion into which the C ring fits on the inner side surface of the cylindrical side surface Is provided,
By covering the vehicle receiving part on the upper part of the vehicle receiving part in which the C ring is accommodated in the C ring fitting groove, and fitting the C ring into the C ring fitting groove of the vehicle receiving part The screw jack is characterized in that the vehicle receiving portion is rotatably attached to an upper portion of the inner cylinder.

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