JP7113400B2 - beam clamp - Google Patents

Description

The present invention relates to an improved beam clamp that is attached to a beam erected by H-shaped steel, I-shaped steel, T-shaped steel, etc., so that a cargo handling device such as a chain block or a hoist can be suspended.

Conventionally, a beam clamp has been widely used for attaching a shaped steel as described above to a beam erected on the ceiling of a building and suspending a cargo handling device such as a chain block (Patent Document 1).
The beam clamp is attached so that it can be opened and closed by opening and closing shafts attached to the lower ends of a pair of left and right clamp arms. The clamp arm is opened and closed by rotating the threaded rods engraved on the left and right sides. Sandwiching grooves are provided on the inner side of the upper end of the clamp arm to sandwich the flanges of the beam from both sides. By tightening the left and right screw rods, the flanges of the beam are sandwiched from both sides, and the beam clamp is fixed at the position. It's like

After that, the hook of the cargo handling device is suspended from the opening/closing shaft provided at the lower end of the clamp arm to carry out the cargo handling work. During cargo handling work, the beam clamp is constantly subjected to various forces from multiple directions from the suspended cargo handling equipment, and the left and right threaded rods sometimes loosen. Since the left and right threaded rods are kept tightened by the frictional force during tightening, once loosened, the looseness expands rapidly, causing the beam clamp to fall off the flange, leading to an accident in which the suspended load falls.

JP-A-2001-234905

However, in conventional beam clamps, it is difficult to visually check the installation state, such as whether the clamping groove of the clamp arm is sufficiently fitted into the flange of the beam, and the feeling of the hand when the handle is fully tightened. I just checked the tightening condition. However, if the left and right threaded rods are rusted or malfunction, even if the left and right threaded rods are intended to be sufficiently tightened, the necessary tightening force will actually be insufficient, and the beam clamp will not work properly during lifting or transportation of the load. There was a danger of falling off the flange of the hoist and falling together with the suspended load, leading to a serious accident.

Equipment such as a beam clamp for handling heavy objects must not fall off from the flange under any circumstances for the above reasons. For this reason, even if the left and right threaded rods become loose, it is necessary to prevent the looseness from expanding. At the same time, when the left and right threaded rods are tightened to attach the beam clamp to the beam, it is also necessary to be able to check the tightening state from the outside.

In view of the above-mentioned problems of the prior art, the first object of the present invention is to prevent loosening of left and right threaded rods of beam clamps during cargo handling work, and even if loosening occurs, the loosening does not expand. The second object is to provide a structure that enables visual confirmation that a necessary and sufficient tightening force has been applied to the flange of the beam to safely lift the load.

In order to achieve the above object, the present invention (claim 1)
A pair of left and right clamp arms 1L, one end of which is attached so as to be openable and closable by the opening/closing shaft 4, and the other end of which is provided with clamping grooves 5L and 5R in which the beam 80 to be attached is fitted.・ 1R and
left and right nut members 2L and 2R provided on the pair of left and right clamp arms 1L and 1R, respectively, and having a left-hand female screw hole 25N in one of them and a right-hand female screw hole 25M in the other;
In the beam clamp A composed of left and right threaded rods 3 for opening and closing clamp arms 1L and 1R that are uniaxially screwed into the left and right nut members 2L and 2R,
The nut member 2R of one clamp arm 1R is
a member body 20R attached to the clamp arm 1R;
The left and right threaded rod 3 is screwed thereon, and is provided so as to be movable in the contact and separation direction with respect to the member body 20R in the axial direction of the left and right threaded rod 3, and when the left and right threaded rod 3 is tightened, the member body 20R a nut block 22R provided with an abutting portion 22t;
a guide bolt 23 provided on the member body 20R parallel to the left and right threaded rod 3 and along the nut block 22R, and engaging with the nut block 22R to limit the amount of separation of the nut block 22R;
A spring 29 is provided between the nut block 22R and the member main body 20R, and presses and urges the nut block 22R in the separation direction from the member main body 20R.

By configuring the beam clamp A in this way, when the left and right screw rods 3 are tightened and fitted into the beam 80 to the depths of the clamping grooves 5L and 5R, the pair of left and right clamp arms 1L and 1R completes the closing operation. do. When the left and right threaded rods 3 are further tightened from this state, the nut block 22R is pushed toward the member main body 20R, and the spring 29 is bent. When the left and right threaded rod 3 is further tightened, the contact portion 22t of the nut block 22R contacts the member main body 20R and the nut block 22R stops. When the left and right threaded rods 3 are further tightened in this state, the left and right threaded rods 3 are fixed by the tightening force to the right and left female screw holes 25M and 25N of the left and right nut blocks 22L and 22R by a strong frictional force. . The flexed spring 29 increases the frictional force by the amount of its elastic force.
As a result, the frictional force is increased compared to the conventional example in which the spring 29 is not present, making it more difficult for the left and right threaded rods 3 to loosen. Acts as a locking mechanism.

The present invention according to claim 2 is the beam clamp A according to claim 1,
The nut block 22R is provided with a guide bolt insertion hole 22g through which the guide bolt 23 is inserted. is formed and
The axial length S from the installation surface 21 of the guide bolt 23 of the member body 20R to the head 23a of the guide bolt 23 is greater than the distance H from the installation surface 21 to the bottom 22s of the counterbored hole 22h. and,
The depth D of the counterbored hole 22h is characterized by being equal to or greater than the height T of the head 23a in the axial direction.

As a result, when the left and right threaded rods 3 are tightened as described above, they are fitted into the beam 80 to the depths of the holding grooves 5L and 5R of the clamp arms 1L and 1R, closing the pair of left and right clamp arms 1L and 1R. At this point the operation ends. A gap K exists between the member main body 20R and the contact portion 22t. When the left and right threaded rods 3 are further tightened from this state, the nut block 22R is pushed toward the member main body 20R and the spring 29 is flexed in the same manner as described above. Then, the head 23a of the guide bolt 23 implanted in the member main body 20R is gradually exposed from the counterbored hole 22h of the nut block 22R. When the nut block 22R is tightened until the contact portion 22t of the nut block 22R contacts the member body 20R, the nut block 22R stops and the head portion 23a is exposed at a height sufficient for visual recognition from the outside. Thereby, the maximum deflection of the spring 29 can be confirmed. After that, the left and right threaded rods 3 are tightened to the fullest extent to complete the attachment of the beam clamp A. The elastic force of the spring 29 is added to the tightening force of the left and right threaded rods 3 to exert a locking effect.

According to claim 3, in the beam clamp A according to claim 1 or 2, a set screw 30 reaching the female threaded hole 25N is screwed on the lower surface of the nut block 22R on the opening/closing shaft 4 side.

According to this, the left and right threaded rod 3 is turned to attach the beam clamp A according to the present invention to the beam 80, and when the attachment is completed, the elastic force of the spring 29 is applied in addition to the tightening force of the left and right threaded rod 3. It is added, and loosening of the left and right threaded rods 3 can be prevented. Even if the left and right threaded rods 3 are loosened, since the elastic force of the springs 29 is always applied, the left and right threaded rods 3 are less likely to be loosened than when the springs 29 are not provided.
In addition, when the left and right threaded rod 3 is tightened, the head 23a of the guide bolt 23 as an indicator provided on the beam clamp A protrudes from the counterbore 22h. As a result, it can be visually confirmed that the left and right threaded rods 3 have been tightened to the maximum tightening position of the spring 29 . If the left and right screw rods 3 are further tightened from this state, it can be confirmed that the beam clamp A has been attached to the beam 80 with the required tightening force.
Furthermore, by providing the set screw 30 on the lower surface of the opening/closing shaft 4 side of the nut block 22R, the set screw 30 can be operated from below while the beam clamp A is attached to the beam 80. 3 can be fixed, and cargo handling work can be carried out safely.

1 is a perspective view of a beam clamp of the present invention attached to a beam; FIG. FIG. 2 is a cross-sectional view taken along line XX of FIG. 1; FIG. 4 is a partial cross-sectional view when the beam clamp of the present invention is tightened; FIG. 4 is a partial cross-sectional view of the beam clamp of the present invention when loosened; 5 is a cross-sectional view taken along line YY of FIG. 4; FIG.

Hereinafter, the present invention will be described in detail according to the illustrated embodiments. The beam clamp A of the present invention includes a pair of left and right clamp arms 1L and 1R, an opening/closing shaft 4 attached to the lower ends of the clamp arms 1L and 1R, left and right nut members 2L and 2R, and opening and closing parts for the clamp arms 1L and 1R. It is composed of left and right threaded rods 3.

A pair of left and right clamp arms 1L and 1R are provided in a symmetrical shape. The front and rear of the left and right clamp arms 1L and 1R are respectively composed of arm members 1Lf and 1Lr/1Rf and 1Rr arranged in the same shape and arranged in the front and rear.
These arm members 1Lf, 1Lr/1Rf, 1Rr are made of elongated oval plates. As can be seen from FIGS. 1 and 2, the lower ends of the arm members 1Lf, 1Lr/1Rf, 1Rr are overlapped with the front arm members 1Lf, 1Rf and overlapped with the rear arm members 1Lr, 1Rr. The opening/closing shaft 4 is attached to the .
As a result, the opening/closing shaft 4 hinges the left and right clamp arms 1L and 1R at the lower end thereof so as to be able to be opened and closed, and this portion becomes a hanging portion of the cargo handling device 90. As shown in FIG. The tip portions (upper end portions) of the arm members 1Lf, 1Lr/1Rf, 1Rr are connected by connecting members 6L, 6R, respectively.

One right nut member 2R is provided at the middle stage of the right clamp arm 1R, and the other left nut member 2L is provided at the middle stage of the left clamp arm 1L.
The left nut member 2L is composed of a left nut block 22L and a collar 20L.
The nut block 22L is a cylindrical member having a right-handed internal thread hole 25M extending through its middle portion at a right angle to its center line. Both front and rear ends of the nut block 22L are rotatably inserted into support holes 1Ls and 1Ls formed in the left arm members 1Lf and 1Lr. A collar 20L is attached to the outer circumference of the nut block 22L, and the end surface of the collar 20L abuts the inner surfaces of the left arm members 1Lf and 1Lr. A threaded rod insertion hole 26L is formed in the collar 20L, and the left and right threaded rods 3 screwed to the nut blocks 22L are inserted therein.

The right nut member 2R is composed of a member main body 20R, a nut block 22R, a guide bolt 23, a spring 29 and a rotation support shaft portion 24R.
The member main body 20R is a rectangular parallelepiped block, and has a block mounting hole 26R in the center and axial holes 28R coaxially formed on both front and rear surfaces thereof. The center line of the shaft hole 28R is orthogonal to the left and right threaded rod 3 and serves as the center of rotation of the member main body 20R.
The rotation support shaft portion 24R is a cylindrical member that is fitted into the shaft hole 28R so as to protrude from the side surface of the member main body 20R and is bolted to the member main body 20R. The rotation support shaft portion 24R may be formed integrally with the member main body 20R.

The right nut member 2R is arranged in the middle portion of the right clamp arm 1R, and the rotation support shaft portion 24R is inserted into the support holes 1Rs and 1Rs coaxially provided in the middle portion of the pair of front and rear arm members 1Rf and 1Rr. rotatably mounted. That is, the right nut member 2R is also rotatably supported around support holes 1Rs, 1Rs provided coaxially in the front and rear.

The right nut block 22R is a cylindrical member in which a left-handed female threaded hole 25N is drilled in line with the central axis, and its outer peripheral surface comprises a small diameter portion 22m, an intermediate diameter portion 22n, and an outer collar portion 22f. is divided into three stages. A stepped portion at the boundary between the small diameter portion 22m and the intermediate diameter portion 22n serves as the contact portion 22t.

The small diameter portion 22m is inserted into the block mounting hole 26R of the member main body 20R so as to be movable in the insertion/removal direction. It abuts on the outer surface of 20R (implantation surface 21 to be described later).
A guide bolt insertion hole 22g is formed in the outer flange portion 22f, and a counterbored hole 22h is formed in alignment with the guide bolt insertion hole 22g so as to open to the outer surface side of the outer flange portion 22f. It is The bottom of the counterbored hole 22h is indicated by 22s. The bottom 22s serves as an engaging portion for the head portion 23a of the guide bolt 23, as will be described later.

Guide bolts 23 are implanted on both sides of the block mounting hole 26R on the surface of the right member main body 20R facing the outer flange portion 22f of the nut block 22R. This surface is referred to as a planting surface 21 .
The shaft portion of the guide bolt 23 is inserted through the guide bolt insertion hole 22g of the outer collar portion 22f, and the head portion 23a is attached to the counterbore hole 22h of the outer collar portion 22f so as to be retractable. That is, the height T of the head 23a is equal to or smaller than the depth D of the counterbore 22h, and the outer diameter of the head 23a is smaller than the inner diameter of the counterbore 22h (see FIG. 3).

A spring 29 is attached between the outer peripheral portion of the intermediate diameter portion 22n of the nut block 22R, that is, between the planting surface 21 of the right member main body 20R and the outer flange portion 22f of the right nut block 22R. , is always pressed and urged in the direction away from the member main body 20R. As can be seen from FIG. 4, the nut block 22R, which is pressed and biased in the separating direction, has the bottom 22s of the counterbored hole 22h of the outer collar portion 22f of the nut block 22R. 23a. At this time, a gap K is generated between the implanted surface 21 and the contact portion 22t of the intermediate diameter portion 22n (Fig. 4).

The left and right threaded rod 3 for opening and closing has a threaded member 3a with a left-handed thread and a right-handed thread arranged side by side at one end and the other end, a handle portion 3b extending from the threaded member 3a, and a handle portion 3b. It is composed of a turning rod 3c which is slidably provided at an end perpendicular to the handle portion 3b. The left and right threaded portions of the left and right threaded rod 3 are screwed into the left and right nut blocks 22L and 22R of the nut members 2L and 2R in the same direction. Therefore, when the left and right threaded rod 3 is rotated, the left and right nut blocks 22L and 22R move in the approaching direction, and reversely move in the separating direction. As a result, the clamp arms 1L and 1R are opened and closed about the open/close shaft 4 via the left and right nut members 2L and 2R.

As shown in FIG. 5, a set screw 30 is attached to the outer flange portion 22f of the right nut block 22R. The threaded hole of this set screw 30 reaches the female threaded hole 25N of the right nut block 22R. Since the installation position of the set screw 30 is on the side of the opening/closing shaft 4, when the beam clamp A is attached to the beam 80, it is located on the lower surface side of the outer collar portion 22f.

In the beam clamp A as described above, the relationship between the member body 20R on one side, the nut block 22R on the right side, and the guide bolt 23 acting as an indicator will be described with reference to FIGS.
The shaft length S (the length of the shaft portion of the guide bolt 23) from the planting surface 21 of the member main body 20R in which the guide bolt 23 is planted to the base end of the head 23a of the guide bolt 23 is the planting surface 21 is larger than the distance H from the planting surface 21 to the bottom 22s of the counterbored hole 22h when the stepped contact portion 22t of the intermediate diameter portion 22n of the nut block 22R is in contact with 21. This difference (shaft length S−distance H) is the gap from the bottom 22s of the counterbored hole 22h to the head 23a, and is equal to the gap K described later.
The depth D of the counterbored hole 22h is equal to or greater than the axial height T of the head 23a.
Therefore, as shown in FIG. 4, when the nut block 22R is pushed away from the member main body 20R by the elastic force of the spring 29 and the head 23a is engaged with the bottom 22s of the counterbore 22h. , the head 23a is embedded in the counterbore 22h and cannot be visually recognized from the outside. At this time, a gap K is generated between the abutting portion 22t, which is a stepped boundary between the small diameter portion 22m and the intermediate diameter portion 22n of the nut block 22R, and the planting surface 21 of the member main body 20R.

On the other hand, as shown in FIG. 3, when the tightening is completed, that is, when the abutting portion 22t abuts against the planting surface 21, the middle portion and above of the head portion 23a are exposed from the counterbore 22h. This exposed portion is indicated at 23b. If the exposed portion 23b is painted in a color that is easy to see from the outside, it will be easy to see from the outside. With the abutting portion 22t in contact with the planting surface 21, the total length W of the intermediate diameter portion 22n and the outer collar portion 22f of the nut block 22R is from the planting surface 21 to the tip of the head 23a of the guide bolt 23. Only the exposed portion 23b is shorter than the length Y to.
If, for example, a thick line 23d is provided between the exposed portion 23b and the non-exposed portion of the head portion 23a, the exposure of the thick line 23d indicates that the abutment portion 22t is in contact with the planting surface 21. It can be confirmed visually. When the left and right threaded rods 3 are fully tightened in this state, the beam clamp A is attached to the beam 80 with the necessary tightening force as will be described later.

Next, how to use this beam clamp A will be described. The clamp arms 1L and 1R of the beam clamp A are opened by turning the handle portion 3b of the left and right threaded rod 3. In this state, as shown in FIG. 4, the right nut block 22R is pressed by the elastic force of the spring 29 and separated from the implanted surface 21 of the member main body 20R, and the head 23a of the guide bolt 23 is It is buried in the counterbored hole 22h and cannot be seen from the outside. Therefore, a gap K is formed between the planting surface 21 of the member main body 20R and the contact portion 22t. The right nut block 22R is held in a separated state by engaging the head 23a of the guide bolt 23 with the bottom 22s of the counterbore 22h, thereby maintaining the open state of the clamp arms 1L and 1R.

In this state, the upper opening between the clamp arms 1L and 1R is inserted from below the beam 80, the clamping grooves 5L and 5R of the clamp arms 1L and 1R are aligned with the flanges 81 of the beam 80, and the left and right screw rods 3 are inserted in this state. reverse. As a result, the clamp arms 1L and 1R are closed around the opening/closing shaft 4, and are tightened with the flanges 81 fitted in the clamping grooves 5L and 5R. At this point, the clamp arms 1L and 1R are closed by the elastic force of the spring 29 while the gap K is maintained.

When the ends of the flanges 81 reach the deep ends of the clamping grooves 5L and 5R, the left and right clamp arms 1L and 1R clamp the flanges 81 from both sides by the elastic force of the springs 29, and the clamping grooves 5L and 5R do not close any more. . Therefore, the left and right nut blocks 22L and 22R also stop in this state. However, at this time, the clamping force is only by the elastic force of the spring 29 as described above, and the gap K exists, so that the tightening force of the clamp arms 1L and 1R to the flange 81 is insufficient. At this point, the head 23a is not exposed.

Then, when the left and right threaded rod 3 is further turned and tightened from this state, the right nut block 22R is gradually screwed toward the right member main body 20R against the spring 29, and the head 23a is exposed. be started. Finally, the contact portion 22t of the intermediate diameter portion 22n is pressed against the planting surface 21 of the right member body 20R. At this time, as the right nut block 22R moves, the head 23a of the guide bolt 23 protrudes from the counterbore 22h and can be visually recognized from the outside. The amount of projection from the counterbore hole 22h of the head 23a of the guide bolt 23 is determined by a predetermined width (for example, by the mark painted surface 23c). After confirming that the complete deflection of the spring 29 can be confirmed visually, the left and right threaded rods 3 are further tightened to the maximum. This completes the tightening with the required tightening force by the left and right threaded rods 3 . Since the spring 29 is flexed at this point, the elastic force is added to the required tightening force.

Finally, the set screw 30 is tightened from below to lock the left and right screw rods 3 to the right nut block 22R. After that, the cargo handling device 90 is suspended from the opening/closing shaft 4 of the beam clamp A fixed to the beam 80, and cargo handling work is performed.
As described above, the beam clamp A receives various forces from various directions from the cargo handling device 90 during cargo handling work. This force always works in the direction of loosening the right and left threaded rod 3 . In the present invention, the elastic force is added to the tightening force of the left and right threaded rod 3 by the spring 29 as described above, so that the left and right threaded rod 3 is prevented from loosening. Even if loosening occurs, the elastic force of the spring 29 always acts on the left and right threaded rod 3, so unless an external force greater than the elastic force of the spring 29 acts, the beam clamp A will suddenly fall off the beam 80. can be prevented.

A: Beam clamp, D: Depth of counterbore hole, H: Distance from installation surface to bottom of counterbore hole, K: Gap, S: Axis from guide bolt installation surface to guide bolt head Length, T: Axial height of the head, W: Total length of the middle diameter portion of the nut block and the outer flange, Y: Length from the installation surface to the tip of the guide bolt head 1L・1R: (left and right) clamp arms, 1Lf / 1Lr / 1Rf / 1Rr: arm members, 1Ls / 1Rs: support holes, 2L / 2R: nut members, 3: left and right threaded rods, 3a: screw members, 3b: handle part, 3c: turning bar, 4: opening/closing shaft, 5L/5R: clamping groove, 6L/6R: connecting member, 20L: collar, 20R: member body, 21: planting surface, 22L/22R: nut block, 22f: outer collar Part 22g: Guide bolt insertion hole 22h: Counterbored hole 22m: Small diameter portion 22n: Intermediate diameter portion 22s: Bottom 22t: Contact portion 23: Guide bolt 23a: Head 23b: Exposure Portion 24R: Rotation support shaft portion 25N: Female screw hole of left screw 25M: Female screw hole of right screw 26L: Threaded rod insertion hole 26R: Block mounting hole 28R: Shaft hole 29: Spring 30: Set Screw, 80: Beam, 81: Flange, 90: Cargo handling device

Claims (3)

a pair of left and right clamp arms, one end of which is attached so as to be openable and closable by an opening/closing shaft, and a clamping groove in which a beam to be attached is fitted on the opposing inner surface of the other end;
left and right nut members provided on each of the pair of left and right clamp arms, one of which has a left-handed female threaded hole and the other of which has a right-handed female threaded hole;
In the beam clamp composed of left and right threaded rods for opening and closing clamp arms that are uniaxially screwed into the left and right nut members,
The nut member of one clamp arm is
a member body attached to the clamp arm;
The left and right threaded rod is screwed thereon, the abutment portion is provided movably in the contact and separation direction with respect to the member body in the axial direction of the left and right threaded rod, and contacts the member body when the left and right threaded rod is tightened. a nut block provided with
a guide bolt provided on the member body parallel to the left and right threaded rod and along the nut block, and engaging with the nut block to limit the separation amount of the nut block;
A beam clamp comprising a spring that is provided between the nut block and the member body and presses and biases the nut block away from the member body . The nut block is provided with a guide bolt insertion hole through which the guide bolt is inserted, and the guide bolt insertion hole is formed with a counterbore through which the head of the guide bolt appears and disappears,
the shaft length from the guide bolt installation surface of the member body to the head of the guide bolt is greater than the distance from the installation surface to the bottom of the counterbored hole,
2. A beam clamp according to claim 1, wherein the depth of said counterbore is equal to or greater than the axial height of said head. 3. A beam clamp according to claim 1, wherein a set screw leading to the female threaded hole is screwed on the lower surface of the nut block on the opening/closing shaft side.

Images