GB2151286A

GB2151286A - Surface vibrator for compacting freshly-placed concrete

Info

Publication number: GB2151286A
Application number: GB08431283A
Authority: GB
Inventors: Harald Wenander
Original assignee: Dynapac AB
Current assignee: Dynapac AB
Priority date: 1983-12-13
Filing date: 1984-12-12
Publication date: 1985-07-17
Also published as: FR2556397A1; SE8306873L; GB8431283D0; SE8306873D0; SE450021B; GB2151286B; DE3441864A1

Abstract

A surface vibrator for compacting freshly-placed concrete comprises an elongated beam (1) to which is imparted a vibratory motion oriented in the longitudinal direction of the beam, the vibratory motion being achieved by means of a rotatably journalled eccentric shaft (3) inside the beam, and wherein the directional vibratory motion is obtained by virtue of the end of the eccentric shaft (3) being journalled on a pivotally journalled arm (4). <IMAGE>

Description

SPECIFICATION Surface vibrator for vibrating concrete surfaces and the like The present invention relates to a surface vibrator for compacting freshly-placed concrete.

In particular the invention concerns an elongated beam to which is imparted a vibratory motion by means of a vibrating unit arranged on the beam. On surface vibrators of the type in question it has proved important for the attainment of efficient compaction of the freshly-placed concrete that the principal component of the vibratory motion is oriented in the longitudinal direction of the beam.

Achieving the longitudinal movement of the beam by means of a connecting rod arranged on the surface vibrator is previously known. Another known method of imparting to the beam a mainly horizontal vibratory motion in its longitudinal direction is by means of a rotating eccentric element which is arranged during rotation to exercise a horizontal impaction effect against one or more stop plates arranged on the beam.

It has also been suggested to mount a circular oscillating eccentric element outside one end of the beam and on leaf springs attached to the beam, the eccentric element having a horizontally oriented eccentric shaft and the leaf springs coinciding in their longitudinal direction with the longitudinal direction of the beam. When the eccentric shaft rotates, the leaf springs absorb the vertically directed vibrational forces while the horizontal forces are transferred to the beam which is thus lent a longitudinal vibratory motion.

The disadvantage of these previously known vibratory element versions is that they are comparatively complicated and occupy considerable space.

Furthermore, there is the danger of concrete readily fastening to them with stoppages or other malfunctions as a result. With the special mounting of the eccentric element outside one end of the beam, its ease of handling both when in use and in transit is also adversely affected.

In order to obtain a uniform vibratory motion along the entire length of the beam, it must be of rigid construction. It should therefore preferably be made of T-section, U-section, Z-section or rectangular cross-section metal. However, the three former sections have the disadvantage that concrete readily fastens in the open spaces and angles formed by their distinctive shapes.

The purpose of the invention is to eliminate the above-mentioned disadvantages and is accordingly aimed at a vibrating beam of rectangular crosssection equipped with a vibrating unit arranged to impart a longitudinal vibratory motion to the beam.

According to the present invention there is provided a surface vibrator for compacting freshlyplaced concrete comprising an elongated hollow vibrating beam of rectangular cross-section equipped with a vibrating unit which is arranged to impart a longitudinal vibratory motion to the beam, the vibrating unit having an eccentric element which comprises a rotatably journalled eccentric shaft oriented vertically inside the beam relative to the base of the beam, and the beam has a drive motor mounted on its top surface with a vertical drive shaft projecting into the beam for driving the eccentric shaft arranged inside the beam.

Particularly characteristic of the invention is that the eccentric element consists of a rotatably journalled eccentric shaft oriented vertically inside the beam, the vibration-generating rotational movement of the shaft being produced by means of a drive motor mounted on the top of the beam.

The inner end of the drive shaft is equipped with a pulley which via a transmission belt is connected so as to drive a pulley mounted on the vertical eccentric shaft. The vertical eccentric shaft is preferably rotatably journalled in one end of an arm which is itself pivotally journalled at its other end on a vertical shaft mounted inside the beam.

The invention will now be described in greater detail by way of example only with reference to the accompanying drawings, in which Figure 1 is a perspective view of a vibrating beam; Figure 2 a vertical cross-section through the beam of Figure 1 and, Figure 3 a horizontal cross-section through the beam.

The vibrating beam 1 depicted in Figure 1 consists of an elongate metal section of rectangular crosssection, which at one end displays a drive motor 2 for driving a vibrating unit arranged inside the beam.

Motor 2 is mounted on the top of beam 1 with its drive shaft oriented vertically relative to the base of the beam (i.e. transverse to the longitudinal axis of the beam and perpendicular to the base) and projecting into beam 1, which arrangement efficiently protects both the vibrating unit and the drive transmission from exposure to concrete attack.

The vibrating unit arranged inside beam 1 consists of an eccentric shaft 3 which is again vertically oriented and rotatably journalled on a pivotally journalled arm 4. Eccentric shaft 3 is given its vibration-generating rotational movement by means of motor 2 via a pulley 6 mounted on motor drive shaft 5 and a pulley 7 mounted on eccentric shaft 3 and also by a transmission belt 8 interacting with these pulleys.

To impart a longitudinal vibratory motion to beam 1 by means of the circular vibration-generating eccentric shaft 3, arm 4 is pivotally journalled inside beam 1 on a vertically oriented shaft 9 arranged at right angles to the longitudinal direction of beam 1.

The circular oscillations generated by eccentric shaft 3 are in the horizontal plane but owing to the pivotal journalling of arm 4, all oscillations at right angles to beam 1 are absorbed by the resilience of transmission belt 8 and in consequence only longitudinal vibrations are imparted to beam 1.

1. A surface vibrator for compacting freshlyplaced concrete comprising an elongated hollow vibrating beam of rectangular cross-section equipped with a vibrating unit which is arranged to impart a longitudinal vibratory motion to the beam, the

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Surface vibrator for vibrating concrete surfaces and the like The present invention relates to a surface vibrator for compacting freshly-placed concrete. In particular the invention concerns an elongated beam to which is imparted a vibratory motion by means of a vibrating unit arranged on the beam. On surface vibrators of the type in question it has proved important for the attainment of efficient compaction of the freshly-placed concrete that the principal component of the vibratory motion is oriented in the longitudinal direction of the beam. Achieving the longitudinal movement of the beam by means of a connecting rod arranged on the surface vibrator is previously known. Another known method of imparting to the beam a mainly horizontal vibratory motion in its longitudinal direction is by means of a rotating eccentric element which is arranged during rotation to exercise a horizontal impaction effect against one or more stop plates arranged on the beam. It has also been suggested to mount a circular oscillating eccentric element outside one end of the beam and on leaf springs attached to the beam, the eccentric element having a horizontally oriented eccentric shaft and the leaf springs coinciding in their longitudinal direction with the longitudinal direction of the beam. When the eccentric shaft rotates, the leaf springs absorb the vertically directed vibrational forces while the horizontal forces are transferred to the beam which is thus lent a longitudinal vibratory motion. The disadvantage of these previously known vibratory element versions is that they are comparatively complicated and occupy considerable space. Furthermore, there is the danger of concrete readily fastening to them with stoppages or other malfunctions as a result. With the special mounting of the eccentric element outside one end of the beam, its ease of handling both when in use and in transit is also adversely affected. In order to obtain a uniform vibratory motion along the entire length of the beam, it must be of rigid construction. It should therefore preferably be made of T-section, U-section, Z-section or rectangular cross-section metal. However, the three former sections have the disadvantage that concrete readily fastens in the open spaces and angles formed by their distinctive shapes. The purpose of the invention is to eliminate the above-mentioned disadvantages and is accordingly aimed at a vibrating beam of rectangular crosssection equipped with a vibrating unit arranged to impart a longitudinal vibratory motion to the beam. According to the present invention there is provided a surface vibrator for compacting freshlyplaced concrete comprising an elongated hollow vibrating beam of rectangular cross-section equipped with a vibrating unit which is arranged to impart a longitudinal vibratory motion to the beam, the vibrating unit having an eccentric element which comprises a rotatably journalled eccentric shaft oriented vertically inside the beam relative to the base of the beam, and the beam has a drive motor mounted on its top surface with a vertical drive shaft projecting into the beam for driving the eccentric shaft arranged inside the beam. Particularly characteristic of the invention is that the eccentric element consists of a rotatably journalled eccentric shaft oriented vertically inside the beam, the vibration-generating rotational movement of the shaft being produced by means of a drive motor mounted on the top of the beam. The inner end of the drive shaft is equipped with a pulley which via a transmission belt is connected so as to drive a pulley mounted on the vertical eccentric shaft. The vertical eccentric shaft is preferably rotatably journalled in one end of an arm which is itself pivotally journalled at its other end on a vertical shaft mounted inside the beam. The invention will now be described in greater detail by way of example only with reference to the accompanying drawings, in which Figure 1 is a perspective view of a vibrating beam; Figure 2 a vertical cross-section through the beam of Figure 1 and, Figure 3 a horizontal cross-section through the beam. The vibrating beam 1 depicted in Figure 1 consists of an elongate metal section of rectangular crosssection, which at one end displays a drive motor 2 for driving a vibrating unit arranged inside the beam. Motor 2 is mounted on the top of beam 1 with its drive shaft oriented vertically relative to the base of the beam (i.e. transverse to the longitudinal axis of the beam and perpendicular to the base) and projecting into beam 1, which arrangement efficiently protects both the vibrating unit and the drive transmission from exposure to concrete attack. The vibrating unit arranged inside beam 1 consists of an eccentric shaft 3 which is again vertically oriented and rotatably journalled on a pivotally journalled arm 4. Eccentric shaft 3 is given its vibration-generating rotational movement by means of motor 2 via a pulley 6 mounted on motor drive shaft 5 and a pulley 7 mounted on eccentric shaft 3 and also by a transmission belt 8 interacting with these pulleys. To impart a longitudinal vibratory motion to beam 1 by means of the circular vibration-generating eccentric shaft 3, arm 4 is pivotally journalled inside beam 1 on a vertically oriented shaft 9 arranged at right angles to the longitudinal direction of beam 1. The circular oscillations generated by eccentric shaft 3 are in the horizontal plane but owing to the pivotal journalling of arm 4, all oscillations at right angles to beam 1 are absorbed by the resilience of transmission belt 8 and in consequence only longitudinal vibrations are imparted to beam 1. CLAIMS

1. A surface vibrator for compacting freshlyplaced concrete comprising an elongated hollow vibrating beam of rectangular cross-section equipped with a vibrating unit which is arranged to impart a longitudinal vibratory motion to the beam, the vibrating unit having an eccentric element which comprises a rotatably journalled eccentric shaft oriented vertically inside the beam relative to the base of the beam, and the beam has a drive motor mounted on its top surface with a vertical drive shaft projecting into the beam for driving the eccentric shaft arranged inside the beam.

2. A surface vibrator as in claim 1 in which the inner end of drive shaft projecting into the beam is equipped with a pulley which via a transmission belt is connected so as to drive a pulley mounted on the vertical eccentric shaft.

3. A surface vibrator as in claim 2, in which the eccentric shaft is rotatably journalled in one end of an arm which is pivotally journalled at its other end on a vertical shaft mounted inside the beam at right angles to the longitudinal direction of the beam.

4. A surface vibrator constructed and arranged and adapted to operate substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.