RU2234454C2 - Safety device-multistep buffer stop - Google Patents

Abstract

FIELD: mechanical engineering; rail cranes.

SUBSTANCE: invention relates to additional safety devices of machines and mechanisms moving along rail tracks, mainly, load-lifting cranes and it is designed for emergency stopping of mechanisms, for instance, in case of failure of crane cutoff devices in motion. Proposed safety device includes housing, drive and travel-motion elements creating friction forces. Said safety device is buffer stop for mechanism or device moving along rail track and provided with travel limiter. Device is made multistep in form of shock-and-friction device housing of which is secured on base for sliding, base being connected with rail for sliding.

EFFECT: improved reliability and faultless operation when stopping mechanisms moving along rail track, especially under abnormal conditions, at overloads appearing in case of failure of cutoff devices.

5 cl, 6 dwg

Description

1. The technical field

The invention relates to additional safety devices of machines and mechanisms moving along the rail, mainly hoisting cranes, and is used mainly for abnormal stopping of mechanisms, for example, in the case of failure of the disconnecting devices of the cranes when moving them.

2. The level of technology

Known deadlock stop shockless type, fixed to the rail with elements that extinguish the energy of a moving crane when stopped with limited impact forces (Mechanization of construction production. Rail tracks of tower cranes. SNiP 3.08.01-85, Gosstroy, M., 1986, p. 11, 36).

The disadvantage of this device is the ability to tilt the crane in the opposite direction to the movement of the crane.

Known dead end stop of shock type, fixed to the rail, absorbing the energy of impact by deformation (Instructions for the device, operation and relocation of rail tracks of building tower cranes. SN 78-79. Gosstroy, M .: Stroyizdat, 1980, p.26). The disadvantage of this device is the ability to tip the crane in the direction of its movement.

It is also known that the safety device adopted by the applicant for the closest analogue includes a housing, a drive in the form of a rod and a spring and moving elements to create friction forces that absorb the impact energy (AS USSR No. 948841, B 66 C 7/16, 1981 )

The device does not take into account the overturning moments of moving mechanisms along the rail track.

3. The invention

3.1. Technical challenge

The technical problem is to increase the reliability and trouble-free operation of the device when stopping the mechanisms moving along the rail, especially under abnormal conditions, when exceeding the maximum loads that occur in cases of failure of the disconnecting devices.

3.2. List of drawings

Figure 1 shows the design of a safety device for stopping a dead end multi-stage crane shock-friction action; figure 2 is a side view along arrow A in figure 1; figure 3 - node I in figure 1 - design of the drive of an eccentric device in a free not clamped position; figure 4 - diagram of the eccentric device in the clamped position; figure 5 is a graph of the forces; in Fig.6 is a graph of the offset (S _t ) of the deadlock on the rail under the force of impact (F), where 1 is the stop housing of the deadlock, 2 is the crane track rail, 3 is the base, 4 is the slider, 5 is the buffer, 6 is box wall, 7 - cam, 8 - cam shaft, 9 - return spring, 10 - pusher, 11 - travel stop, 12 - bolt connection, 13 - clamp plate to the pedestal, 14 - cam drive lever, 15 - clamp plate to rail, 16 — pedestal, 17 — pedestal emphasis, 18 — pedestal plate, 19 — pedestal base, 20 — box-shaped structure; F (F ₁ , F ₂ , F ₃ ) - the force of the crane on the safety device, F _П1 = F ₁ - the force of pressing the deadlock against the pedestal, F _P2 - the force of pressing the deadlock to the rail, K - safety factor, Q - calculated shear force, f — friction coefficient, S _T — displacement of the deadlock under the force F, W — eccentric clamping force, M — eccentric moment, l — shoulder, S — eccentric drive lever, r _cp — average radius the center of rotation of the eccentric at the clamping point, α _cp is the average elevation angle of the eccentric at the clamping point, φ, φ ₁ are the friction angles slip at the clamping point on the axis of the eccentric.

3.3. Features

The safety device includes a housing, a drive and moving elements with the possibility of creating frictional forces. In contrast to the known one, the safety device is a dead end stop for a mechanism or device moving along a rail, with a travel stop, made multi-stage, in the form of a shock-friction device, in which the housing is fixed to the pedestal with the possibility of sliding along it, the pedestal is connected to the rail with the possibility of sliding on the rail.

The housing is made in the form of a box wall connected to the base and to the slider on which the buffer is mounted, and the housing through the base is connected to the pedestal by a bolted connection with a pressing force F ₁ equal to:

where K ₁ - coefficient of safety of adhesion,

Q ₁ - the estimated shear sliding force (kgf),

f ₁ - coefficient of friction.

The shock-friction device is equipped with an eccentric with a drive in the form of a rod and a return spring mounted on the housing of the dead end stop, with an eccentric clamping force equal to:

where M = S × l is the moment on the eccentric (kgf · cm),

l - shoulder (cm),

S - lever force (kgf),

r _cp is the average value of the radius from the center of rotation of the eccentric to the clamping point (cm),

α _cp is the average elevation angle of the eccentric at the clamping point (degrees),

φ, φ ₁ - sliding friction angles at the clamping point on the axis of the eccentric (degrees),

the eccentric drive is made in the form of a pivotally connected eccentric drive lever, a drive rod, a return spring and a pusher.

The pedestal is made in the form of a box-shaped structure with a base, a stop and a plate, the pedestal through the base is connected to the rail by a bolted connection with a pressing force of Fp ₂ equal to:

where K ₂ - coefficient of safety of adhesion,

Q ₂ - estimated shear sliding force (kgf),

f ₂ - coefficient of friction.

Additionally, the device can be equipped with an emergency stop operating in the zone of additional restrictions.

3.4. Device essence

The safety device is a multi-stage deadlock stop for a mechanism or device moving along a rail with a movement limiter 11, made in the form of a shock-friction device, in which the slider 4 for perceiving impacts consists of a box-shaped wall 6 connected to the base 3 and has a flange with buffer installed 5.

The base case is bolted to the plate of the pedestal 18 with the possibility of sliding on it to create friction forces that smoothly absorb shock effects. An eccentric 7 with levers, rods, springs and a pusher is mounted on the shaft inside the slider.

The pedestal is made in the form of a box-shaped structure 20 with a base 19, a stop 17 and a plate 18, the pedestal through the base is connected to the rail by a bolted connection with the possibility of movement along the rail.

The device operates as follows.

The principle of operation of the device is based on a stepwise-smooth quenching of impact energy by friction forces and provides a smooth stop of a mechanism or device moving on rails without the occurrence of both positive and negative critical tipping moments.

When hitting a dead end of the mechanism, such as a crane, in case the impact force does not exceed the value F1 (Fig.5, 6), the mechanism is inhibited by the deformation of the buffer; if the impact force exceeds the value of F1, then the slide moves along the plate of the pedestal (braking by friction); if the force exceeds the value of F ₂ , then the pusher in contact with the emphasis of the pedestal acts through the pusher, springs, rods, levers and shaft on the eccentric, turning it to press it against the plate of the pedestal and increasing the friction force; if the force exceeds the value of F ₃ , then the pedestal glides along the rail (repeated braking by friction). For emergency situations, if the force value F ₄ is exceeded, the device is equipped with an emergency limiter 11.

4. Information confirming the possibility of carrying out the invention

The calculation of the structural elements of the device is based on the possible acting forces, while an emergency situation can occur under extreme conditions, such as in hurricane winds. Under normal conditions, deadlocks are designed for minimum applied impact forces.

For a crane up to 30 t with a travel speed of up to 100 m / min, the impact-friction dead end stop has dimensions 1600 × 700 mm, shear force 9.6 tf (tightening force Fзat = F ₁ = 9.6 tf), with the number of bolts 10 pieces. - the tightening torque of the bolt is 15.4 kgf · m with the number of bolts 10 pcs. The response limits of the respective elements are shown in figure 5.

Claims (5)

1. A safety device including a housing, a drive and moving elements with the possibility of creating frictional forces, characterized in that the safety device is a deadlock stop for a mechanism or device moving along a rail, with a travel stop, made multi-stage, in the form of a shock-friction device in which the housing is fixed to the pedestal with the possibility of sliding along it, the pedestal is connected to the rail with the possibility of sliding along the rail. 2. The device according to claim 1, characterized in that the housing is made in the form of a box-shaped wall connected to the base and to the slider on which the buffer is mounted, the housing through the base is connected to the pedestal by bolt connection with a pressing force F _P1 equal to

where K ₁ - clutch safety factor; Q ₁ - calculated shear sliding force, kgf; f ₁ - coefficient of friction. 3. The device according to claim 1, characterized in that the impact-friction device is equipped with an eccentric with a drive mounted on the housing of the dead end stop with an eccentric clamping force equal to

where M = S · l - moment on the eccentric, kgf · cm;

- shoulder eccentric, cm; S - effort on the lever, kgf; r _cf - the average value of the radius from the center of rotation of the eccentric to the clamping point, cm; α _cf - the average angle of elevation of the eccentric at the clamping point, degrees; φ, φ ₁ - sliding friction angles at the clamping point on the axis of the eccentric (degrees), the eccentric drive is made in the form of a pivotally connected eccentric drive lever, a drive rod, a return spring and a pusher. 4. The device according to claim 1, characterized in that the pedestal is made in the form of a box-shaped structure with a base, a stop and a plate, the pedestal through the base is connected to the rail by a bolted connection with a pressing force F _P2 equal to:

where K ₂ - coefficient of safety of adhesion; Q ₂ - estimated shear sliding force, kgf; f ₂ - coefficient of friction. 5. The device according to claim 1, characterized in that it is additionally equipped with an emergency limiter.

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