JP3298622B2 - Crane backstop shock absorber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crane backstop shock absorber.

[0002]

2. Description of the Related Art FIG. 7 shows a conventional cradle.
1 is a boom, 2 is a hook, and is wound up by a hook winding drum 4 by a hoisting rope 3. Reference numeral 5 denotes a pendant loop for supporting the beam 1 and a sheave 7 provided on a live mast 6.
The boom 1 is turned upside down by the boom hoisting rope 8 wound around the boom. Reference numeral 9 denotes a hoisting drum of a boom hoisting rope 8. 10 is a backstop.

A conventional backstop is shown in FIG. The backstop 10 is provided between the lower portion of the boom 1 and the base of the live mast 6, and is provided at one end of the boom 1 as shown in FIG. ) 14
And a spring 12 that expands and contracts as the boom moves up and down. With this configuration, if the boom undulation is excessively wound beyond the full compression of the spring 12, or if the boom is long, the boom backstop 10 is moved by wind or load from the front.
Is often damaged.

[0004]

Problems to be solved by the present invention are as follows: (1) Minimize the damage of the crane beam when it is overwound, and minimize the number of replacement parts even if it is damaged. (2) Prevent a major accident due to damage (3) It is an object to provide a safe backstop even if an operation error occurs.

[0005]

SUMMARY OF THE INVENTION A spring or hydraulic cylinder backstop of a crane provided between the base of a boom and a live post has a built-in shear pin which breaks before being damaged by overwinding. Then, even after the shear pin is broken, the cushioning action of the spring or the hydraulic cylinder can be maintained.

[0006]

FIG. 1 shows details of a backstop 15 according to the present invention. When the boom 1 is hoisted, the front end roller 16 of the backstop 15 provided with the hydraulic cylinder 17 (see FIG. 4) rises on the rail 13 and the tail end at the upper end of the rail for receiving the backstop. Hits get14. Further winding causes the hydraulic cylinder of the backstop 15 to contract while applying a constant pressure (FIG. 2). When the boom 1 is further wound up, the roller 16 at the tip becomes the minimum length as shown in FIG. At this point, any further mistakes in winding will result in damage.

The crane's boom backstop 15
Normally, limit switches, potentiometers, etc., such as spring type and hydraulic cylinder type, are used before they reach the full compression length.
For example, the automatic stop is set with a margin. A ratchet-type pawl is set on the undulating drum, and when the pawl is activated due to the automatic stop, it often cannot be lowered to the lower side, so the automatic stop function is released and the pawl is further wound up and the pawl is raised. You need to lower the boom. Occasionally, the operator forgets to release the operator, works, breaks the backstop beyond the limit, and knocks the boom backward.

According to the present invention, when the boom is wound up beyond this limit, the boom backstop 15 is provided with a shock absorbing device for absorbing an impact to minimize breakage due to excessive overwinding. is there.

In FIG. 4, the backstop 15 has a shock absorbing bumper 18 in addition to a hydraulic cylinder 17. The hydraulic cylinder 17 and the absorbing bumper 18 are bolted by a flange 19. The hydraulic cylinder 17 includes a contraction side pipe a and an extension side pipe b, and a directional control valve 21 via a check valve 20.
, And further connected to a hydraulic pump 22. 23
Is a safety valve. In FIG. 4, if the roller 16 contracts the distance D due to overwinding, the boom will break or the backstop will break. Therefore, the distance D shrinks mode in the previous -e ₁ point - Instrument limiter potentiometer - are exercising use conditions regulatory functions by motor and limit switches.

FIG. 5 shows details of the shock absorbing damper 18. Reference numeral 24 denotes a cylinder into which a piston 25 is fitted. The piston 25 includes a tip small diameter portion 25a, an intermediate large diameter portion 25b, a flange 25c, and a mounting portion 25d. A further most distal end portion 25e of the distal small diameter portion 25a is slidably fitted in a guide ring 26 provided at an end of the cylinder 24. A coil spring (or disc spring) 27 is fitted at an initial pressure P ₁ on the outer periphery of the small-diameter portion 25a.

The large-diameter portion 25b is slidable in the cylinder 24, and a shear pin 28 that penetrates in the middle in the diametric direction and reaches the cylinder 24 is mounted. Both ends of the shear pin 28 are stopped by covers 29. Shear pin 28
As shown in FIG. 5B, a notch 30 is provided between the outer diameter of the intermediate large-diameter portion 25b of the piston and the inner diameter of the cylinder 24 in the circumferential direction.

In FIG. 5, the dimension between the center of the flange 19 and the center of the mounting hole 31 of the mounting portion 25d is usually set at A. When an excessive compressive force is applied, pressure is applied to the shear pin 28 via the cylinder 24, and the notch 30 of the shear pin 28 is sheared. While spring 27 is Aru incorporates an initial force P _1, shear - the pins 28 are sheared, the spring 2
7 Nikakaru reaction force, increases in the range of P ₁ of P _2, the impact force is relaxed.

The guide ring 26 retains its shape, and even after the shear pin 28 is broken, the shock absorbing damper 18 can be regenerated only by replacing the shear pin 28. Note e ₁₃ in FIG. 5 is shear - in clearance after the pin 28 is broken, which may be either presence or absence. When the shear pin 28 is broken, the maximum
_At this time, the initial dimension A becomes (A-e ₁₂ ). The spring 27 is moved in a range of P ₁ to P _2, stroke - click e
_In the range of _12, the shock caused by the breakage of the shear pin 28 is absorbed. Even if the shear pin 28 is damaged, the expendable supplies are the shear pin 2
8. About 27 springs, others can be reused.

[0014]

According to the present invention, since the shock absorbing bumper is provided on the backstop, breakage of the backstop when the crane boom is excessively wound can be minimized. Shock absorbing bumpers - in the shear - providing pins, which also damaged, since damping force of the spring 27 becomes P ₁ to P ₂ and the large, to maintain the damping force, thereby preventing a large accident. It is economical because replacement parts can be minimized even after breakage. Even if there is an operation error and overwinding occurs, as described above, the number of damaged parts is small and a major accident can be prevented,
It is suitable as a safety device for a vehicle.

[Brief description of the drawings]

FIG. 1 shows a backstop comprising a hydraulic cylinder and a shock absorbing bumper of the present invention.

FIG. 2 shows a state in which the film is wound up and hits a target 14;

FIG. 3 shows a state in which the film is wound up too much.

FIG. 4 is a configuration of a hydraulic cylinder portion of a backstop.

FIG. 5 is a configuration of a shock absorbing bumper unit.

FIG. 6 shows a state of the shock absorbing bumper when the shear pin is broken.

FIG. 7 is a known chloraclean.

FIG. 8 is a back stop of a known cradle.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Boom 2 Hook 3 Hoisting rope 4 Hook hoisting drum 5 Pendant loop 6 Live mast 7 Sheave 8 Boom undulating roll
P 9 Hoisting drum 10 Backstop 11 Roller 12 Spring 13 Rail 14 Target 15 Backstop 16 Tip roller 17 Hydraulic cylinder 18 Shock absorbing bumper 19 Flange 20 Check valve 21 Directional switching valve 22 Hydraulic Pump 23 Safety valve 24 Cylinder 25 Piston 25a Tip narrow part 25b Intermediate large diameter part 25c Flange 25d Mounting part 25e Foremost part 26 Guide ring 27 Spring 28 Shear pin 29 Cover 30 Notch 31 Mounting hole

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-7-172774 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B66C 23/88 B66C 23/92

Claims (1)

(57) [Claims] A crane spring-type or hydraulic cylinder-type backstop provided between a boom and a base of a live mast, the backstop being attached to the base of the live mast or the lower part of the boom. comprising a shock-absorbing bumpers to prevent damage due to excessive winding, piston the impact absorbing bumpers is a flange via mounting cylinder and in the cylinder to the end of the backstop, which is biased by a spring initial force P ₁ Wherein the piston is supported by a shear pin passing through the cylinder.