Hook device

Details Hook device Hook device

1999-12-20

2001-10-23

Browne, Lynne H. (Department: 3629)

Joints and connections

Laterally related members connected by latch means, e.g.,...

C403S196000, C052S655100, C052S749100

Reexamination Certificate

active

06305868

ABSTRACT:

BACKGROUND OF THE INVENTION
The present invention relates to hook devices for use in assembling temporary scaffolds and built-in work platforms at construction sites.
Such hook devices are fixed to pipes, one at each end of the pipe, or to a scaffold board, in a pair to each of opposite ends of the board, and then removably fitted to other members fixed to the scaffold or work platform. Already known is a hook device which comprises a hook body having an inverted U-shaped inner peripheral surface formed by an upper wall, a front wall and a rear wall and fittable to a member to be connected, a stopper disposed in a stopper space formed in the hook body and having a retaining portion projectable beyond a lower end of the rear wall of the hook body toward a lower end of the front wall for preventing the hook body from slipping off the member to be connected by engagement therewith, the stopper being movable from a slipping-off preventing position to a slipping-off permitting position in which the retaining portion is positioned away from the lower end of the front wall to permit the hook body to slip off the member to be connected, an elastic member for biasing the stopper toward the slipping-off preventing position, and a connecting pin extending between and attached to opposite side walls of the hook body defining the stopper space for connecting together the hook body, the stopper and the elastic member, the connecting pin having an intermediate portion loosely inserted through a hole formed in the stopper to render the stopper pivotally movable about the axis of the connecting pin.
Although the stopper is required for the hook device to assure safety, the stopper will interfere with work, for example, when the temporary scaffold is disassembled. Stated more specifically, when the pipe or scaffold board provided with the hook device is to be removed, there arises a need to move the stopper to the slipping-off permitting position against the biasing force of the elastic member. Although immovable while being held by hand, the stopper returns to the slipping-off preventing position if released from the hand. It is therefore impossible to disassemble the scaffold or work platform by one person, hence the problem of a poor work efficiency.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a hook device which is adapted to achieve an improved work efficiency in assembling temporary scaffolds or built-up work platforms at construction sites.
The present invention provides a hook device which comprises a hook body having an inverted U-shaped inner peripheral surface formed by an upper wall, a front wall and a rear wall and fittable to a member to be connected, a stopper disposed in a stopper space formed in the hook body and having a retaining portion projectable beyond a lower end of the rear wall of the hook body toward a lower end of the front wall for preventing the hook body from slipping off the member to be connected by engagement therewith, the stopper being movable from a slipping-off preventing position to a slipping-off permitting position in which the retaining portion is positioned away from the lower end of the front wall to permit the hook body to slip off the member to be connected, an elastic member for biasing the stopper toward the slipping-off preventing position, and a connecting pin extending between and attached to opposite side walls of the hook body defining the stopper space for connecting together the hook body, the stopper and the elastic member, the hook device being characterized in that the stopper is formed with a slot having an intermediate portion of the connecting pin inserted therethrough, the slot comprising a stopper guide portion for permitting the stopper to move between the slipping-off preventing position and the slipping-off permitting position, and a stopper lock portion extending from the stopper guide portion and allowing the connecting pin to engage in when the stopper is moved from the slipping-off permitting position further toward a direction opposite to the slipping-off preventing position.
When the hook device is fitted to a member having a circular cross section and to be connected to another member or pipe, the retaining portion of the stopper is first moved from the slipping-off preventing position to the slipping permitting position by being pushed by the member to be connected, and thereafter returned to the slipping-off preventing position by being biased by the elastic member upon the hook body fitting to the member to be connected. When the stopper is moved from the slipping-off permitting position further in a direction opposite to the slipping-off preventing position, the connecting pin fits into the stopper lock portion of the slot, whereby the stopper is restrained from moving while permitting slipping off. Thus, the hook device is made readily removable from the member to be connected. Accordingly, when a pipe or scaffold board fixedly provided with such hook devices at its opposite ends is to be removed, the stopper of each hook device is held in the slipping-off permitting position against movement, and the pipe or scaffold board is then lifted in its entirety, whereby the pipe or board can be removed easily.
Preferably, a projection is provided on each of opposite side surfaces of the stopper, and the hook body is formed with a guide groove for guiding the stopper. While the slotted portion of the stopper is guided by the connecting pin, each projection of the stopper is then additionally guided by the guide groove of the hook body, rendering the stopper smoothly movable.
Preferably, the elastic member is a double torsion coil spring, and the connecting pin is inserted through coil portions of the elastic member, the elastic member having a joined end retained by an engaging portion on the hook body and free ends bearing on the projections of the stopper for biasing the stopper toward the slipping-off preventing position. A proper elastic force then acts on the stopper, enabling the connecting pin to connect the hook body, the stopper and the elastic member with greater ease.
Preferably, the stopper has an unlocking knob portion projecting upward from the stopper space, and the connecting pin as fitted in the stopper lock portion is movable into the stopper guide portion by moving the knob portion toward the slipping-off preventing position. The stopper can then be returned to the slipping-off preventing position easily.
Preferably, the hook device further comprises means for returning the unlocking knob portion toward the slipping-off preventing position while the hook body is being removed from the member to be connected or while the hook body is being fitted to the member. The stopper, which is brought to the slipping-off permitting position once, then returns to the slipping-off preventing position upon the hook body being fitted to the member to be connected. This eliminates the manual procedure for moving the unlocking knob of the stopper, further obviating the likelihood of using the hook device in such an unstable state that the hook body is fitted to the member with the stopper in the slipping-off permitting position.
Preferably, the stopper returning means comprises an elastic member, a stopper return lever for transmitting the elastic force of the elastic member to the stopper, and a pivot for pivotally moving the stopper return lever thereon, and the stopper return lever is formed at an upper end thereof with a stopper pushing portion opposed to the stopper from below when the stopper is in the slipping-off permitting position with the hook body fitted around the member, an elastic force acting on a lower end of the stopper return lever. As the hook body is removed from the member to be connected, the elastic force of the elastic member moves the stopper return lever about the pivot, consequently causing the stopper pushing portion to give the stopper an upward force, i.e., a force to move the unlocking knob toward the slipping-off preventing position. The stopper is moved toward

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