JPH0229113Y2 - - Google Patents

Description

[Detailed description of the invention] "Industrial application field" This invention has a pantograph mechanism formed on the base, and the lifting platform is raised and lowered by the rotation of a threaded rod mounted between substantially horizontally opposing corners. Regarding the pantograph type jack.

``Prior Art'' An example of a conventional jack is shown in FIG. 1.

That is, in the jack 10, a pantograph mechanism 30 is formed on a base 20, and corner portions A and B are rotated by rotation of a threaded rod 40 installed between corner portions A and B that face each other horizontally. The lifting platform 50 is raised and lowered in close proximity to each other or in a spaced apart manner.

The pantograph mechanism 30 has lower links 31, 31
and the upper links 32, 32, a pivot between the lower link 31 and the upper link 32 on one side is formed by a corner screw member 33 at the corner part A, and a pivot on the other side is formed by the corner insertion member 34 at the corner part B. It is formed.

The lower links 31, 31 are pivotally supported by the support bracket 21 of the base 20 via pivot pins 22, 22, and are connected via a connecting bracket 23, and the base ends of the lower links 31, 31 are connected to the gear portion 31.
a and 31a.

The upper links 32, 32 are pivotally supported by the support bracket 51 of the lifting platform 50 via pivot pins 52, 52 and are connected via a connecting bracket 53, and the tips of the upper links 32, 32 are connected to the gear portion 32.
a and 32a.

The threaded rod 40 has a normal threaded portion 41 that has a general winding direction, a round shaft portion 42, and a handle engagement bracket that is fixed to the end of the round shaft portion 42 and engages with an operating handle (not shown). 43 is provided, the normal threaded portion 41 is screwed to the corner threaded member 33, the round shaft portion 42 is loosely fitted to the corner insertion member 34, and a thrust bearing 4 is provided on the back surface of the corner insertion member 34.
4. The pressure receiving surface 46 of the handle engaging bracket 43 is brought into pressure contact with the washer 45.

However, such conventional jacks10
Now, when using the jack 10, the lifting platform 50
The area where the
0 lifts the object, it is necessary to raise the platform 50 considerably without any load being lifted, but the speed at which corner portions A and B approach each other is determined by the pitch of the normal threaded portion 41. Therefore, it is necessary to rotate the screw rod 40 without any load being applied, and for example, a considerable amount of time is wasted between installing the screw rod 10 below the vehicle and actually lifting the vehicle. ,
There was a problem in that it was difficult to use, as it made the operator feel irritated and impatient when there was an emergency.

``Purpose of the invention'' The present invention was made by focusing on the problems of the conventional method.Until the jack actually functions, it rises quickly, and when lifting an object, it does not work like the conventional method. The purpose of the present invention is to provide a jack that can sufficiently exert its power and solve the above problems.

"Structure of the invention" In order to achieve the above object, the present invention provides a pantograph in which a pantograph mechanism is formed on a base, and a lifting platform is raised and lowered by rotation of a threaded rod installed between substantially horizontally opposing corners. In the type jack, a normal threaded part is formed on one side of the threaded rod and a reverse threaded part on the other side, and the normal threaded part is screwed into a corner threaded member provided on one of the substantially horizontally opposing corner parts of the pantograph mechanism. and the reverse threaded portion is loosely fitted into a corner insertion member provided on the other side of the corner portion, and is screwed into a nut member that slides directly or indirectly on the outer surface of the corner insertion member, and when no load is applied, or A jack characterized in that a torque limiting member is provided which locks the nut member so as not to rotate until a predetermined torque is reached when a small load is applied, and allows the nut member to rotate when the predetermined torque is exceeded. When no load is being applied, the corner insertion member moves through the corner screw member and nut member due to the normal threaded portion and the reverse threaded portion, and the corner portions move toward or away from each other and move up and down quickly, and the load is removed. In the past, when actually lifting an object, the nut member would idle and the corner parts would approach or separate from each other using only the corner screw member to exert sufficient force.

“Embodiment” An embodiment of the present invention will be described below based on the drawings. Note that the same parts as in the conventional example are given the same reference numerals and redundant explanations will be omitted.

FIGS. 2 to 7 show an embodiment of the present invention, and as shown in FIG. 2, a normal threaded portion 41 is formed on the tip end side of a threaded rod 40 as in the conventional example. However, a reverse threaded portion 47 is formed on the proximal end side to which the handle engagement bracket 43 is fixed. The length of the reverse threaded portion 47 is shorter than that of the normal threaded portion 41.

As shown in FIGS. 3 to 5, the jack 10a
In the corner portion B, the reverse threaded portion 47 of the threaded rod 40 is loosely fitted into the corner insertion member 34, and a thrust bearing 44 is provided in contact with the back surface 34a of the corner insertion member 34. Similarly, the threaded rod 40 is loosely fitted, and a nut member 60 is provided further outside the thrust bearing 44, and the reverse threaded portion 47 is screwed into this nut member 60. Note that the nut member 60 is directly connected to the nut member 60 without going through the thrust bearing 44.
may be brought into contact with the back surface 34a of the corner insertion member 34.

As shown in FIGS. 6 and 7, the nut member 60 has a cylindrical center shaft with a threaded hole 61 screwed into the reverse threaded portion 47, and has inclined surfaces 62a, 6 on the outer periphery.
Restriction grooves 62, 62, .

The corner insertion member 34, the thrust bearing 44, and the nut member 60 are built into the end bracket 35, which has a horizontally grooved shape and is fixed to the corner insertion member 34 via screws 35a, 35a. holds down the back surface 63 of the nut member 60, and a reverse threaded portion 47 is inserted into the rear wall 35b.

A torque limiting member 70 capable of locking the nut member 60 up to a predetermined torque is fixed to the side wall 35c of the end bracket 35 with screws 71, 71. The torque limiting member 70 includes an engagement hook 73 that is elastically supported at the tip of a support arm 72 that extends around the outer periphery of the nut member 60.
The engagement hook 73 is elastically abutted against the bottom of the restriction groove 62 of the nut member 60.

The engagement hook 73 of the torque limiting member 70 locks the nut member 60 in a non-rotatable manner to a predetermined torque when there is no load on the lifting platform 50 or when the load is small, and attempts to rotate the nut member 60. When the force increases and exceeds the predetermined torque, the biasing force is set to such an extent that the engaging hook 73 is disengaged from the limiting groove 62 of the nut member 60 and becomes rotatable.

In the jack 10a having the above configuration, when the lifting platform 50 is at a low position and no load is applied as shown in FIG.
When rotated, the normal threaded part 41, which is threaded into the corner threaded part 33, moves relative to the corner threaded member 33, and the reverse threaded part 47 is threaded into the nut member 60, and the nut member 60 is rotated. 60 is locked by the torque limiting member 70, so it also moves relatively, and the corner portion A and the corner portion B approach each other, and the approaching speed is faster than that of the normal threaded portion 41 and the reverse threaded portion 47.
Since both move at the same time, it is much faster than when only one moves, and the lifting platform 50 quickly comes into contact with the object. At this time, the handle engaging bracket 43 and the end of the threaded rod 40 on the reverse threaded portion 47 side protrude from the end bracket 35.

When the lifting platform 50 comes into contact with the object and lifts up, and a load is applied, the load is transmitted to the nut member 60 via the corner insertion member 34 and the thrust bearing 44, and the thread groove of the nut member 60 and the reverse thread The sliding resistance between the portion 47 and the threads increases, and this sliding resistance increases as the load of the lifting platform 50 increases.

When the load applied to the lifting platform 50 becomes larger than the set value, the nut member 60 is pulled by the rotational force of the reverse threaded portion 47 due to the sliding resistance between the thread groove of the nut member 60 and the thread of the reverse threaded portion 47. becomes larger, and the engaging hook 73 of the torque limiting member 70 that locks the nut member 60 rises and climbs over the slope 62a of the limiting groove 62, so that the torque limiting member 70 locks the nut member 60. The nut member 60 can no longer be held in place, and the nut member 60 begins to rotate together with the reverse threaded portion 47.

Therefore, there is no relative rotation between the nut member 60 and the reverse threaded portion 47 of the threaded rod 40, and the nut member 60 does not move relative to the reverse threaded portion 47. Part B approaches only due to the relative movement between the normal threaded part 41 and the corner threaded member 33 due to the rotation of the normal threaded part 41, the rising speed of the lifting platform 50 becomes slower, and the lifting force of the jack 10a is the same as before. becomes powerful.

When lowering the elevator platform 50, the operating handle is rotated in the opposite direction. While a load exceeding the set value is applied to the lifting platform 50, the engagement hook 73 of the torque limiting member 70 is held in place by the nut member 6, as in the case of lifting.
Since the nut member 60 rises and overcomes the inclined surface 62b of the zero restriction groove 62, the nut member 60 rotates together with the reverse threaded portion 47, and the elevator platform 50 gradually descends.

When the load applied to the lifting platform 50 becomes lower than the set value by sufficiently descending, the support arm portion 72 of the torque limiting member 70 fits into the limiting groove 62 of the nut member 60 and locks the nut member 60. The member 60 and the reverse threaded portion 47 of the threaded rod 40 rotate relative to each other, and the nut member 60 moves relative to the threaded rod 40. Corner screw member 33
The corner insertion member 34 approaches and quickly descends.

"Effects of the invention" According to the jack according to the invention, when the screw rod is rotated, when no load is applied to the lifting platform or when the load is small, the corner parts automatically approach each other quickly and at high speed. When the lifting platform is activated and the platform is brought into actual contact with the object, and the platform is in contact with the object and receives its load,
The nut member that is in sliding contact with the corner insertion member rotates together with the threaded rod, so the platform rises gently.
It is now possible to obtain the same strong lifting force as before, and there is no need for dynamic operations to change the state, and it operates automatically, making it extremely easy to use, eliminating unnecessary movements, and eliminating the need for emergencies. It is possible to quickly raise the object even when the situation arises.

[Brief explanation of the drawing]

Figure 1 is a vertical cross-sectional view of a conventional jack, Figure 2~
Fig. 7 shows an embodiment of the present invention, Fig. 2 is a front view of the threaded rod, Fig. 3 is a partial vertical sectional view near corner B, and Fig. 4 is also shown with the end bracket removed. Plan view, Figure 5 is a sectional view taken along line V-V in Figure 4,
FIG. 6 is a front view of the nut member, and FIG. 7 is a side view of the nut member. 10, 10a... Jacket, 20... Base, 3
0... Pantograph mechanism, 33... Corner threaded member, 34... Corner insertion member, 40... Threaded rod, 41... Right threaded part, 47... Reverse threaded part, 50
... Lifting platform, 60 ... Nut member, 70 ... Torque limiting member.

Claims (1)

[Scope of Claim for Utility Model Registration] In a pantograph type jack in which a pantograph mechanism is formed on a base and a lifting platform is raised and lowered by the rotation of a threaded rod installed between substantially horizontally opposing corners, one side of the threaded rod A normal threaded part is formed on one side and a reverse threaded part is formed on the other side, and the normal threaded part is screwed into a corner threaded member provided on one of the substantially horizontally opposing corner parts of the pantograph mechanism, and the said normal threaded part is formed on the other side of the corner part. The reverse threaded portion is loosely fitted into the corner insertion member, and is screwed onto a nut member that directly or indirectly slides into contact with the outer surface of the corner insertion member, until the specified torque is reached when no load is applied or when the load is small. A jack characterized in that a torque limiting member is provided which locks the nut member in a non-rotatable manner and allows the nut member to rotate when the predetermined torque is exceeded.