GB2183598A - Anti-descending safety device in hydraulic jack - Google Patents

Abstract

A hydraulic jack has an anti-descending safety device comprising a notched plate (41), engageable by a pivotable support (42); a connecting plate (43) being mounted on the same pivot axis and fixed to the support (42) via a rotatable cylinder (47). A cable (46) is attached to the plate (43) at one end and is actuated via a lever (471) to rotate the plate (43) and hence the support (42), to disengage the support (42), against a spring-loading. Plate (41) is mounted on the elevating arm (31). <IMAGE>

Description

SPECIFICATION Anti-descending safety device in hydraulic jack Background ofthe invention The present invention relates to a hydraulicjack safety device, and in particular, to a anti-descending safety device which can be used to prevent the falling back of heavy load accidentally as a result of oil leakage in hydraulic jack.

Generally, hydraulic jack can be divided into two majorgroups, i.e. hydraulic garagejackand hydraulic floorjack, hydraulic system is employed to operate an elevating arm, sothata heavy load can be elevated to an optimum height. Generally, the sealing of hydraulic fluid in this case enable the internal fluid pressure to be above 500 kg/cm2, however, to maintain such a high pressurefora long time, the sealing ofthe hydraulic fluid may be damaged and oil leakage resulted, i.e., the heavy load will be descended accidentally and causes damages to the op eratorandthe load as well.

It is therefore a primary object of the present invention to obviate the disadvantages of the prior art as described above and to provide a hydraulic jack antidescending safety device such that the heavy load on hydraulic jack is prevented from descending accidentally as a result of oil leakage in hydraulic system.

Another object of the present invention to provide a hydraulicjack anti-descending safety device which allows the userand the load is free from damaging.

A still further object of the present invention is to provide a hydraulic jack anti-descending safety device which is compact in size and thus easily operated.

Other objects, advantages and novel features of the present invention will become appa rent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.

Figure lisa perspectiveviewshowingthe hydraulicjack with safety device constructed in ac- cordance with one embodiment ofthe present invention; Figure2 is a schematic, side elevation view showing the embodiment of the present invention; Figure3 is a cross-section view taken along the line-Y-Y in Figure 2; Figure its a cross-section view taken along the lineX-X in Figure2 when at locking position; Figure 4-2 is anothercross-section view taken along the line X-X in Figure 2 when at lock releasing position.

Referring now to Figure 1 and Figure 2, there is shown a hydraulicjackwith descending safetydevice constructed in accordance with one embodiment of the present invention. The present invention essentially comprising of a left and right supporting body (1 ) (1'), hydraulic system (2), elevating means (3) and anti-descending device (4) and etc.

The left and right supporting body (1) (1') has symmetrical shape and arranged in parallel, atthe right of left supporting body(1), a holder (12) for handle is provided for retaining a handle; a spring (13) is connected in between left (1) and right (1') supporting body. Hydrauliccylinder(21 ),fluid-storagetube (22) and oil-returning device (23) are within the space formed by said left (1) and right (1') supporting body.

The elevating means (3) essentially comprising of elevating arm (31), load holder (33), load holdersupport (32) and elevating-arm shaft (34); wherein, said elevating arm (31) is within said leftand rightsupporting body (1) (1') moreover, it can be moved up and down, load-holder support (32) is connected to one end of elevating arm (31), while the load holder (33) isforthe retaining of loads.

The aforementioned elements and functions are priorart,which are not to be discussed in detail.

The present invention, typically, the characteristic of anti-descending safety device (4) is included: geared plate (41), geared plate support (42), connecting plate (43), spring (44), supporting shaft (45), cable (46) and rotating cylinder (47); wherein geared plate (41) is a arch shaped plate forming with gears, and along the interior of gears of geared-plate, a row of reverse gears (411) is designed, the said gears (411) is located such that said geared plate support (42) can be engaged with the reverse gears (411), additionally, one end of geared-plate (41) can be soldered with the elevating arm (31) and formed a unit, and said geared-plate (41) is up-down extended or retracted about the elevating-arm shaft (34) as the centre with said elevating arm (31).

Geared-plate support (42) is disposed to supporting shaft (45) by means of a fitting cylinder (431) as shown in Figure 3, and the ends of supporting shaft (45) is screwed tight to the left and right supporting body (1) (1 ') by means of nuts; as can be seen clearly in Figure 2, at one end of geared-plate support (42), a recess (421) is provided such that the recess (421) can be engaged with the reverse gear (411) of geared plate (41).

Referring now to Figure 3, there is shown across- section view ofthe structure of anti-descending safety device. As shown, connecting plate (43) and geared plate support (42) is soldered to the fitting cylinder (431) and formed into an unit, moreover, the unit is mounted to supporting shaft (45) and therefore, it can be moved upward and downward, one end of connecting plate (43) is connected with a spring (44), the aforementioned geared plate support (42) is controlled by the spring (44),therefore, it can be slided into said geared plate (41), in this way,the elevating arm (31) is not affected during the erection of elevating means (3); one end of cable (46) is connected to said connecting plate (43) and the other end is hooked to the rotating cylinder (47) after passing through the aperture which is provided on the left supporting body (1), and said rotating cylinder (42) is mounted at the exteriorwall of let supporting body (1) (please referto Figure 1).

Referring now to Figure 4-1 and Figure 4-2,there is shown the cross-section view taken along the line X X, As shown, rotating cylinder (47) is a cam-like structure, one end of said cylinder (47) is disposed with a controlling handle (471), and rotating cylinder (47) is locked to the exterior of left supporting body (1) by a shafting peg (please referto Figure 4-1), wherein within said rotating cylinder (47) a spring (473) and a ball bearing (474) are provided. The ball bearing (474) can be exactly fitted to the slot (11).Referring now to Figure4-2,the ball bearing (474) of rotating bar (47) is secured tightly into the slot (11) of said left supporting body (1) by means of spring (473), i.e., at lock-releasing position; cable (46) is controlling the connecting plate (43) and enablethe geared plate support (42) can be released from geared plate (41), therefore, the final position of geared plate support (42) is shown as dotted line in Figure 2.

However, as shown in Figure 4-1, if the ball bearing (474) of rotating cylinder (47) is released from said slot(1 1) left supporting body (1), i.e., at locking position, moreover, the pulling force of spring (473) enables the geared supporting plate (42) to move to the right,while elevating arm (31) is extended, said geared supporting plate (42) is slided along geared plate (41), therefore, it causes no blockage while at elevating position, however, if the elevating arm is descending, the reverse gear(411) of geared plate (41) is engaged with the recess (421) of said gearedplate support (42),therefore, it acts as a antidescending safety device.

The following description discloses the steps of operation of hydraulic jack anti-descending safety device; (a) raising load operation: (1) oil-returning device (23) is closed by rotating said (device) clockwise (as shown in Figure 2); (2) rotating cylinder (47) is set at locking position, i.e. ball bearing (474) is released from the slot (11) of left supporting body (1); (3) a handle is fitted into a handle holder (12) and move up and down manually, in this way, the piston valve which connected to said handle holder(12) is moved up and down with respectto said handle (not shown), as a result the hydraulic fluid is transmitted; (4) gradually, the elevating arm (31) is extended, since said geared plate (41) is connected with said elevating arm (31), therefore, said elevating arm (31) is moved with elevating shaft (34) as the centre;; (b) anti-descending safety device in operation: When geared plate support (42) is at locking position, i.e. the recess (421) of geared plate support (42) is engaged with the reverse gears (411) of geared plate (41), therefore the elevating arm (31) is stopped from descending action, hence, it attains the purpose of anti-descending (as shown in Figure 2).

The following description discloses generally the descending action of hydraulic jack: (1) ifa heavy load which placed on load holder (33) is to be descended,firstly, the rotating cylinder (47) is set at lock-releasing position (as shown in Figure 4-2), which permit ball bearing (474) to beengaged with the slot (11) of left supporting body (1), moreover, since it is connected by said cable (46), in turn, it moves said connecting plate (43) and the position of geared plate support (42) as shown by dotted line in Figure 2, i.e. the geared-plate support (42) is released from geared plate (41); (2) oil-returning device (23) is opened by rotating counter-clockwise, in this way, the hydraulic fluid in hydraulic cylinder(21) is recycled backto fluid stor- age tube (22); ; (3) atthistime,the pulling force of spring (13) causes said elevating arm (31) to be retracted to its lowest position.

While the above provides a full and complete disclosure of the preferred embodiments ofthe present invention, various modifications, alternate constructions and equivalents may be employed withoutdeparting from the true spiritand scope of the invention. Therefore, the above description and illustration should not be constructed as limiting the scope of the invention, which is defined by the appended claims.

Claims (2)

1. A hydraulic jack anti-descending safety device, which comprising of a left and right supporting body, hydraulicfluid cylinder, elevating means and anti-descending elements; wherein said hydraulic fluid cylinder and one end of elevating arm are disposed within the space between left and rightsupporting body; anti-descending means comprising of a geared plate, geared plate support, connecting plate, spring, supporting shaft, cable, rotating cylin demand etc.; wherein said geared plate is a archshaped plate with gears, reverse gears are provided attheinneredgewhich is meantforthe engagement of said geared plate support, moreover, said geared plate and elevating arm are integrated to form an unit; geared-plate support is secured to a supporting shaft by means of a holderwhile both endsofsupporting shaft is secured to said left and rightsupporting body, the recess of geared-plate support can be engaged with said reverse gears; by means of holder, connecting plate is integ rated with geared plate support and secured to a supporting shaft and permitted up and down movement, one end of said connecting plate is connected to a spring while one end of connecting plate is connected to a cable, in turn, the cable is secured to a rotating cylinder which dis- - posed at the exterior of left supporting body; a handle is disposed perpendicularly to said rotating cylinder, a spring and a ball bearing is disposed within said rotating cylinder and it can be engaged with the slot of left supporting body.

2. A hydraulicjack provided with an antidescending safety device, comprising a geared or toothed plate, a geared plate support or detent and a connecting plate acting to move the detent; and elevating arm being assembled as a unit in which the support or detent is secured to a transverse support shaft around which the connecting plate is also pivotable upwards or downwards in accordance with an operating cable and against a spring bias, the cable being secured to a rotatable cylinderwith an operating handle and a spring and ball-bearing latching means.