CZ301648B6 - Crank for hand-operated jack - Google Patents

Abstract

In the present invention, there is disclosed a crank (1) for a hand-operated jack, said crank (1) having an arm (2) being coupled at its one end via a freewheeling clutch with a jack driving shaft while at its other end the arm (2) is provided with a handle (3). The handle (3) can swing on the arm (2) in three positions (A, B, C) û two working positions (A, B) and one transport positions (C). In the first working position (A) the handle (3) forms along with the arm (2) the crank (1), in the second working position (B) it forms a level of the length (L) being equal to the sum of the arm (2) length (L1) and the length (L2) of the handle (3), and in the transport position (C) the handle (3) abuts the arm (2). An arrestment mechanism of all the three positions (A, B, C) of the handle (3) is attached to the arm (2). The arrestment mechanism (11) consists of a segment provided with a location hole for a pin (13) representing an axis (4) of handle (3) tilting wherein said axis (4) is parallel to a plane (10) of the arm (2) turning. The handle (3) is formed by a pin (5) and a tubular casing (6) inserted thereon and axially pressed by a spring (7) into a recess (12) in the arrestment mechanism (11) wherein each position (A, B, C) of the handle (3) has its own recess (12).

Description

Technical field

The invention relates to the field of lifting mechanisms, in particular to a crank of a manually operated jack.

BACKGROUND OF THE INVENTION

Especially for assembly and repair work in various industries, manually operated portable jacks are used for free-load handling, which means mainly lifting, lowering, pushing and expanding,

These manually operated portable jacks are mostly rack-mounted and hand cranked for manual operation. The handle consists of a shoulder and a handle. At the end of the arm, the handle is hinged between a working position in which it lies perpendicular to the arm and can be rotated by the handle and a transport position in which the handle is tilted to the arm. The jacks are equipped with freewheel clutches, mostly with a ratchet and latch optionally operating in either of the two crank sensing directions, ie, in both possible senses of the actuating movements. These freewheel clutches, also called ratchet clutches, allow the jack to be operated by repeatedly turning and returning the crank to its initial position. This is used when there is not enough space to rotate the crank over the full 360 degree range.

Working with these jacks is quite strenuous and especially when handling loads whose weight is at the limit of the nominal load of the jack, it is necessary to exert a relatively large control force on the handle. This is particularly noticeable in dead positions where the handle is in the up or down position. It is difficult to control these jacks even in confined spaces.

Although handles are known whose handles are angularly adjustable relative to the arm, their adjustment is laborious because it requires the operation of both hands. With one hand, it is necessary to slide the locking member out of engagement with the locking claws formed on the handle, in this position, while turning the handle into the desired position with the other hand. The locking member, the locking claw handle and the guide arm for the locking member are complex manufacturing parts. Moreover, these known handles do not allow a position where the handle abuts the shoulder and minimizes transport dimensions.

SUMMARY OF THE INVENTION

These drawbacks are substantially eliminated by a crank for a manually operated jack, in particular a ratchet, whose arm is connected at one end via a freewheel clutch to the jack drive shaft and at the other end is provided with a hinged handle between two working positions; the arm forms a crank and, in a second working position, a lever equal to the sum of the length of the arm and the length of the handle; a locking mechanism of the working positions of the handle in the form of a segment provided with a pin receiving hole characterized in that the handle is formed by a pin and a tubular sleeve axially pushed by the spring into the recess in the locking device, with one recess corresponding to each operating position of the handle.

A third recess is formed in the locking device into which the tubular sleeve is axially pressed by a spring when the handle is in a transport position in which it rests against the arm after tilting from the first working position.

-1 CZ 301648 B6

The crank for a manually operated jack according to the invention facilitates the jack control by extending the crank arm with a folded handle to form a jack control lever. The lever arm is extended by the length of the handle compared to the crank arm, which means a reduction in the actuating force. The lever allows you to operate the jack even in confined spaces. The lever is operated by simply swinging and returning the lever to its initial position. The adjustment of the crank according to the invention is simple, essentially without any added components. The jack control can be combined in terms of crank - lever as required and according to the specific operating conditions. Changing the lever to the lever and vice versa is simple and virtually instantaneous without mounting operations by only one hand on the handle. The same applies to the transition to and from the transport position of the handle.

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BRIEF DESCRIPTION OF THE DRAWINGS

An exemplary embodiment of a crank for a manually operated jack according to the invention is shown in the accompanying drawings, in which Fig. 1 is a handle with a handle in a transport position in a direction of the plane of rotation of the arm; 3 is an axonometric view of the handle with the locking device. FIG.

DETAILED DESCRIPTION OF THE INVENTION

The hand-operated rack jack (not shown) is provided with a crank handle 1. The crank 1 has an arm 2 which, at one end with a hub 8, is supported by an overrunning clutch on the drive shaft of the jack. 1 and 2, the ratchet 9 is arranged in the hub 8 and cooperates with a pawl which is mounted on the jack housing. At the other end, the arm 2 is provided with a hinged handle 3. The handle 3 is hinged between three lockable positions A, B, C, two of which A, B are working and the third C is transportable.

In the first working position A, the handle 3 with the arm 2 forms a normal crank 1, by turning of which the jack is operated. In the second operating position B, the handle 3 with the arm 2 forms a lever L equal to the sum of the length L1 of the arm 2 and the length L2 of the handle 3. By repeatedly oscillating and returning this lever to its initial position, the jack is operated.

A locking device 11 of the handle 3 is provided on the arm 2 in individual positions A, B, C. The locking device 11 is formed in the form of a segment firmly connected to the arm 2 and having a receiving hole for a pin 13 which forms the axis 4 of the handle. The handle 3 is mounted on the pin 13 by the end of its pin 5. The handle 3 is further comprised of a tubular sleeve 6 mounted on the pin 5 and axially pushed by a spring 7 towards the axis 4 of the handle tip 3. The end of the tubular sleeve 6 in the respective positions A, B, C of the handle 3 engages the respective recess 12 in the segment of the detent device 11 *

Before using a jack having a handle 3 locked in transport position C, depending on the specific conditions of the jack location, the handle 3 is folded about axis 4 either by 90 degrees to the first working position A, in which it forms a normal handle 1 with arm 2, or 180 degrees to the second working position B, in which with the arm 2 creates a lever of length L. After adjusting the idle clutch for the desired sense of movement can be used jack, operated either by crank 1 or lever. Folding of the handle 3 between any positions A, B, C is possible only with the tubular sleeve 6 axially pulled against the force of the spring 7, when it disengages from engagement with the appropriate recess 12 of the arresting device LL. the housing 6 disengages and the spring 7 presses it into engagement with the corresponding recess 12 of the locking device 11.

Claims (2)

PATENT CLAIMS Crank (1) for a manually operated jack, in particular a ratchet, the arm (2) of which is connected at one end via a freewheel clutch to the jack drive shaft and is provided with a handle (3) hinged between two working positions (A, B) ), wherein in the first working position (A) the handle (3) and the arm (2) form a crank (1) and in the second working position (B) a lever of length io (L) equal to the sum of the length (L1) of the arm (2); length (L2) of the handle (3), the locking device (11) of the operating positions (A, B) of the handle (3) in the form of a segment provided with a pin receiving hole (13) forming the axis (4) is attached to the arm (2) tilting of the handle (3), characterized in that the handle (3) is formed by a pin (5) and a tubular sleeve (6) mounted thereon axially pressed by a spring (7) into a recess (12) in the locking device (11) with each working 15, one recess (12) corresponds to the position (A, B) of the handle (3). Crank according to claim 1, characterized in that a third recess (12) is formed in the locking device (11), into which the tubular sleeve (6) is axially pressed by a spring (7) when the handle (3) is in the transport a position (C) in which it is adjacent to the arm (2) after folding down from the 20 of the first operating position (A).