WO2000014007A1

WO2000014007A1 - A jack

Info

Publication number: WO2000014007A1
Application number: PCT/AU1999/000746
Authority: WO
Inventors: Sergio Cotellessa
Original assignee: Concept 2000 Pty Ltd
Priority date: 1998-09-09
Filing date: 1999-09-09
Publication date: 2000-03-16
Also published as: AUPP580598A0

Abstract

Hand operated jack (10) comprises a housing (12) through which slide bar (14) extends. Slide bar (14) has a foot (16) at one end for bearing on a support surface. Support member (18) is carried by the housing (12) to support an object to be lifted from the support surface. A one way drive mechanism (20) is held within housing (12) and provided with a pivotal trigger lever (22) for the operation thereof. Drive mechanism (20) includes a plate (26) through which the slide bar (14) extends. By pulling on the trigger lever (22), the plate (26) grips the slide bar (14) forcing it to move in a first direction (F). This increases the distance between the foot (16) and member (18) thereby providing a lifting action. Brake mechanism (24) is provided for normally engaging the slide bar (14) to prevent motion in an opposite direction (S). The brake mechanism (24) is switchable to a free state in which it disengages the slide bar (14) to allow it to slide in direction (S) enabling the foot (16) to move toward the support member (18).

Description

Title A JACK

Field of the Invention

The present invention relates to a jack and in particular, to a hand trigger operator jack.

Background of the Invention

Many different types of jacks are known. Perhaps the most common type is the car jack which is used for changing a wheel of a vehicle. Two varieties of the car jack are the screw jack and the hydraulic jack. The screw jack comprises four arms pivotally connected in a parallelogram structure with an elongate screw threadingly coupled at diametrically opposed apexes of the parallelogram. A separate ratchet lever can engage one end of the screw for turning the screw. This causes the threading coupled apexes to travel either toward each other or away from each other thereby lifting or lowering the jack. Hydraulic jacks typically comprise a cylinder filled with a hydraulic fluid and a displacement mechanism such as a piston which can be forced to travel through the piston by operation of a screw lever. Turning the screw lever in one direction forces the piston through the cylinder thereby extending the jack.

Another type of jack comprises an elongate rack of teeth and a spring biased pawl housed within a slidable collar on the rack. A separate lever can be used for disengaging the pawl from successive teeth and lifting the collar upwardly along the rack.

The above-mentioned jacks are very effective in performing their designed tasks. Nevertheless, they are not particularly well suited for domestic or "handy man" use. One reason for this is that the base of the jack and the lifting point of the jack are separated by a substantial distance even when the jack is in its lowest position. This is due to the inherent design of such jacks which operate on the basis that the lifting point is spaced above the ground. However, this spacing prevents such jacks from easily being used in lifting domestic articles such as filing cabinets, washing machines and fridges because they physically cannot get beneath such articles. Also, these types of jacks require separate levers for operation which may be lost. Further, because of their bulk, size and weight they are often difficult to accurately manoeuvre and position. Additionally, these jacks are relatively expensive to manufacture because of the number of components required and the gauge of the steel components required.

Summary of the Invention

It is an object of the present invention to provide a jack of relatively simple construction and well suited to domestic/handyman use.

According to the present invention, there is provided a hand operated jack comprising at least: a housing through which a slide bar extends, the slide bar provided at one end with a foot for bearing on a support surface; a support member carried by and extending from the housing for supporting an object to be lifted; a one-way drive mechanism held retained by the housing and provided with a pivotal trigger lever for operation thereof, the drive mechanism adapted for driving the slide bar relative to the housing in a first direction which results in the support member moving away from the foot; and, a brake mechanism for normally engaging the slide bar to prevent relative motion of the slide bar and housing in a second opposite direction, the brake mechanism switchable to a free state in which it disengages the slide bar allowing the slide bar to slide relative to the housing in the second direction enabling the support member to move toward the foot; whereby, in use, an object which is supported on a support surface can be jacked or lifted by placing the foot on the support surface, locating the support member under the object and pulling the trigger lever one or more times to move the support member away from the foot so that the support member lifts the object from the support surface. Preferably the drive mechanism comprises a drive plate having a recess through which the slide bar passes and first biasing means for biasing the drive plate toward a position in which the drive plate is disengaged from the slide bar, the drive plate and the first biasing means located in the housing, and wherein the trigger lever is arranged to abut the drive plate on a side so as to be able to push the drive plate against the bias provided by the first biasing means, whereby, in use, when the trigger lever is pivoted by an initial angle, it pushes the drive plate against the first biasing means causing the drive plate to pivot relative to the slide bar so that edges of the recess engage the slide bar and where upon further pivoting the trigger lever drives the drive plate and the slide bar relative to the housing in the first direction against the first biasing means moving the support member away from the foot thus lifting an object supported on the support member.

Preferably the housing is provided with a stop against which the drive plate is urged by the first biasing means prior to pivoting of the trigger lever.

Preferably the first biasing means comprises a helical spring through which the slide bar extends.

Preferably the brake mechanism comprises a brake lever having a recess through which the slide bar passes, a second stop for abuting one end of the brake plate and second biasing means for biasing the brake plate about the second stop so that edges of the recess engage the slide bar, an opposite end of the brake plate being accessible through the housing so that pressure can be applied thereto to pivot the brake plate against the second biasing means to disengage the recess of the brake plate from the slide bar allowing the slide bar to slide relative to the housing in the second direction moving the support member toward the foot.

Preferably the second biasing means comprises a helical spring through which the slide bar extends.

Preferably the support member is formed separately of the housing. Preferably the support member is provided with a lug through which the slide bar passes.

Preferably the support member is arranged so that it can be disposed at the same level or below the level of the foot.

Preferably the slide bar is of circular transverse section and rotatable about its axis within the housing.

Brief Description of the Drawings

An embodiment of the jack will now be described by way of example only with reference to the accompanying drawings in which:

Figure 1 is a plan view of the jack with its housing opened;

Figure 2 is a plan view of a drive plate of the jack;

Figure 3 is a plan view of a brake plate of the jack;

Figure 4 is an end view of a half of the housing of the jack; and,

Figure 5 is a plan view of a foot of the housing of the jack.

Detailed Description of the Preferred Embodiment

The hand operated jack 10 comprises a housing 12 through which a slide bar 14 extends. The slide bar is provided at a lower end with a foot 16 for bearing on a support surface (not shown). A support member 18 is carried by and extends from the housing 12 for supporting an object (not shown) to be lifted from the support surface. A one way drive mechanism 20 is held within the housing 12 and provided with a pivotal trigger lever 22 for operation thereof. The drive mechanism 20 is adapted for driving the slide bar 14 relative to housing 12 in a first direction which is equivalent to the slide bar 14 moving in a direction (indicated by arrow F) which results in the support member 18 moving away from the foot 16. Brake mechanism 24 is provided for normally engaging the slide bar 14 to prevent relative motion of the slide bar 14 and housing 12 in a second opposite direction to the first direction (which is equivalent to slide bar 14 moving in direction S). The brake mechanism 24 is switchable to a free state in which it disengages the slide bar 14 to allow the slide bar 14 to slide in direction S which then enables the foot 16 to move toward the support member 18. In use, an object which is supported on a support surface can be jacked or lifted by placing the foot 16 on the support surface, locating the support member 18 under the object and pulling the trigger lever 22 one or more times. As the trigger lever 22 is pulled it pulls the housing up the slide bar 14 in direction S to move the support member 18 away from the foot 16 thereby lifting the object.

Drive mechanism 20 comprises a drive plate 26 which is retained within a cavity 28 in the housing 12. Plate 26 bears against the stop 30 which is in the form of a wall 32 extending inwardly from peripheral wall 34 of the housing 12 and is provided with two hemispherical protrusions 36. The stop 30 also includes a boss 38 extending inwardly from an inside surface of a side wall of the housing 12. The boss 38 is spaced from the wall 32 to allow the slide bar 14 to pass therebetween. Bias means in the form of a helical spring 40 is located about a length of the slide bar 14 and abuts at one end against one side of the plate 26. An opposite end of spring 40 abuts against an internal wall 42 formed in the housing 12. The wall 42 is provided with a hemispherical cut-out 44 to accommodate the passage of slide bar 14.

Plate 26 is provided with a recess in the form of hole 46 through which slide bar 14 passes (see Figure 2). When no pressure is exerted by trigger lever 22, the spring 28 pushes the plate 26 against the stop 30 into a position where it is substantially perpendicular to the length of the slide bar 14. In this position, the edges of hole 46 are disengaged from bar 16 so that the slide bar 16 would be able, in the absence of the brake mechanism 24, slide through the hole 46. A second additional free floating plate 26' (shown in phantom in Figure 1) of identical form to plate 26 can be placed adjacent plate 26 to improve the gripping/holding power of the drive mechanism 20. In this case the spring 40 would abut against plate 26' rather than directly against plate 26.

Brake mechanism 24 comprises a brake plate 48 provided with a recess in the form of hole 50 through which the bar 14 passes. A major length of the brake plate 48 is disposed within a cavity 52 formed inside the housing 12. However, end 54 of the plate 48 extends through an opening 56 in the housing 12 to allow for manipulation. Opposite end 58 of the plate 48 bears against an internal stop 60 formed within housing 12. Spring 62 is held in compression between side 64 of the plate 48 and an internal wall 66 in the housing 12 so as to pivot the plate 48 about stop 60 in the direction S. As a result of this, the edge of hole 50 engage the bar 14 and thus prevent the bar 14 from being pushed or slid in the direction S, or from the point of view of housing 12, the housing 12 is prevented from sliding down bar 14 in direction F. It will be appreciated that any force applied on bar 16 in the direction S would simply tend to further pivot the plate 48 about stop 60 in direction S to increase the force of engagement between the plate 48 and bar 14. Semi-circular cutout 67 is formed in wall 66 to allow for the passage of slide bar 14.

Support member 18 is in the form of a thin strip of metal which is bent so as to have a central portion 68 and tabs 70 and 72 which extend from opposite ends of portion 68 parallel to each other but in opposite directions. Tab 72 is disposed within a cavity 74 formed in the housing 12 between internal wall 42 and end wall 76. A hole is provided in the tab 74 through which the bar 14 passes. Tab 70 extends at right angles away from slide bar 14. Semi-circular cut-out 77 is formed in end wall 76 to allow for the passage fo slide bar 14.

Trigger lever 22 is pivoted about boss 78 which extends from the inside surface of the side wall of housing 12. When no force is applied to trigger lever 22, it sits in an equilibrium position in which its head 80 is contacted on one side by a lower sloped portion 82 of internal wall 66 and a side of plate 26 opposite spring 40. Trigger arm 22 extends through opening 84 formed in the peripheral wall 34 of housing 12.

Tapped screw holes 86 are formed on various internal walls of the housing 12 to allow for the screwing together of the shell halves of the housing 12. One shell half 12A is depicted in Figure 1. The other shell half (not shown) is of a shape and configuration substantially symmetrical with shell half 12A.

As shown in Figure 5, the foot 16 is essentially in the form of a square plate with a recess 88 formed centrally along one side thereof. The recess is provided for accommodating the portion 68 of support member 18 so that the tab 70 can be disposed at the same level, or lower than the foot 16.

Handle 90 is integrally formed with housing 12 and is located near trigger lever 22 so that the handle 90 can sit in the palm of a user and the fingers of the user grip the lever 22.

When in the equilibrium position shown in Figure 1, the plate 26 is substantially perpendicular to bar 14 and therefore is disengaged therefrom and the brake plate 48 is pivoted in the direction S about stop 60 so as to engage slide bar 14. The engagement by brake plate 48 prevents the slide bar 14 from being slid within housing 12 in the direction S. As discussed above, applying force to the bar 14 in direction S simply increases the force of engagement between plate 48 and the bar 14. However, the brake mechanism 24 does not prevent the slide bar 14 from being slid within housing 12 in the direction F. When a force is applied in direction F, the brake plate 48 will pivot against the bias of spring 62 so as to disengage from slide bar 14 allowing the sliding motion.

When it is desired to lift an object with the jack 10, the foot 16 is placed on the surface on which the object itself sits. The support member 18 is then located beneath the object or a jack point of the object. If, prior to use, the support member

18 is above the jack point, end 54 of plate 48 can be depressed thereby disengaging the brake plate 48 from slide bar 14 so that the housing can be slid down the slide bar 14 in direction F.

In order to lift the object, the trigger lever 22 is squeezed and pivots about boss 78. When this occurs, head 80 pushes the plate 26 so that it is urged to pivot in direction F about the protrusions 36 and against the bias of spring 40. After a short degree of pivoting, the edge of hole 46 engages the slide bar 14. Further pivoting of trigger lever 22 causes the plate 26 to be pushed in the direction F against the bias of spring 40, carrying with it the slide bar 14. In this way, the housing 12 and support 18 are advanced in direction S up along slide bar 14. When lever 22 is released, spring 40 pushes the plate 26 against the stop 30 and the handle 22 returns to the position shown in Figure 1. Housing 12 remains in this advanced position as the brake mechanism 24 prevents it from moving down bar 14 in direction F. Accordingly, the foot 16 and support member 18 are moved apart relative to each other. Thus, as the object is supported on the support member 18, the object is also lifted from the support surface (ie. the ground).

Repeated pulling of the trigger lever 22 further advances the housing 12 and support surface 18 along slide bar 16 in a direction S increasing the degree of lift provided by the jack 10.

From the above description, it will be apparent that embodiments of the jack 10 are particularly well suited for domestic and/or "handy man" use. The jack 10 is self contained in that it does not require the use of separate components for its actuation.

Also, the lifting point provided by the support member 18 can be disposed at the same level as or below the foot 16 of the jack. Further, the jack is light in weight and therefore easy to accurately manoeuvre and manipulate and is also incredibly easy to use as it only requires the squeezing of a trigger lever 22 and the depression of a brake plate 48. Indeed, both the trigger lever 22 and brake plate 48 can be manipulated without the hand moving from the handle 90. Now that an embodiment of the invention has been described in detail, it will be apparent to those skilled in the relevant arts that numerous modifications and variations may be made without departing from the basic inventive concepts. For example, the slide bar 14 can be of any transverse section or shape such as circular, elliptical, rectangular etc. Also, the foot 16 and support member 18 can adopt any configuration which will allow the support member 18 to be at least at the same level, if not below, the foot 16. Also, the springs 40 and 42 can be replaced with other bias elements.

All such modifications and variations are deemed to be within the scope of the present invention, the nature of which is to be determined from the foregoing description and the appended claims.

Claims

The Claims Defining the Invention are as Follows:

1. A hand operated jack comprising at least: a housing through which a slide bar extends, the slide bar provided at one end with a foot for bearing on a support surface; a support member carried by and extending from the housing for supporting an object to be lifted; a one-way drive mechanism held retained by the housing and provided with a pivotal trigger lever for operation thereof, the drive mechanism adapted for driving the slide bar relative to the housing in a first direction which results in the support member moving away from the foot; and, a brake mechanism for normally engaging the slide bar to prevent relative motion of the slide bar and housing in a second opposite direction, the brake mechanism switchable to a free state in which it disengages the slide bar allowing the slide bar to slide relative to the housing in the second direction enabling the support member to move toward the foot; whereby, in use, an object which is supported on a support surface can be jacked or lifted by placing the foot on the support surface, locating the support member under the object and pulling the trigger lever one or more times to move the support member away from the foot so that the support member lifts the object from the support surface.

2. A hand operated jack according to claim 1 wherein the drive mechanism comprises a drive plate having a recess through which the slide bar passes and first biasing means for biasing the drive plate toward a position in which the drive plate is disengaged from the slide bar, the drive plate and the first biasing means located in the housing, and wherein the trigger lever is arranged to abut the drive plate on a side so as to be able to push the drive plate against the bias provided by the first biasing means, whereby, in use, when the trigger lever is pivoted by an initial angle, it pushes the drive plate against the first biasing means causing the drive plate to pivot relative to the slide bar so that edges of the recess engage the slide bar and where upon further pivoting the trigger lever drives the drive plate and the slide bar relative to the housing in the first direction against the first biasing means moving the support member away from the foot thus lifting an object supported on the support member.

3. A hand operated jack according to claim 1 or 2 wherein the housing is provided with a stop against which the drive plate is urged by the first biasing means prior to pivoting of the trigger lever.

4. A hand operated jack according to claim 3 wherein the first biasing means comprises a helical spring through which the slide bar extends.

5. A hand operated jack according to anyone of claims 1 to 4 wherein the brake mechanism comprises a brake lever having a recess through which the slide bar passes, a second stop for abuting one end of the brake plate and second biasing means for biasing the brake plate about the second stop so that edges of the recess engage the slide bar, an opposite end of the brake plate being accessible through the housing so that pressure can be applied thereto to pivot the brake plate against the second biasing means to disengage the recess of the brake plate from the slide bar allowing the slide bar to slide relative to the housing in the second direction moving the support member toward the foot.

6. A hand operated jack according to claim 5 wherein the second biasing means comprises a helical spring through which the slide bar extends.

7. A hand operated jack according to any one of claims 1 to 6 wherein the support member is formed separately of the housing.

8. A hand operated jack according to claim 7 wherein the support member is provided with a lug through which the slide bar passes.

9. A hand operated jack according to any one of claims 1 to 8 wherein the support member is arranged so that it can be disposed at the same level or below the level of the foot.

10. A hand operated jack according to any one of claims 1 to 9 wherein the slide bar is of circular transverse section and rotatable about its axis within the housing.