A double-acting hydraulic impact hammer includes a drop weight and an inner hydraulic piston. The drop weight is arranged to be driven in an upward and downward direction and the drop weight acts on a pile during its downward motion. The piston has a voided internal area defining a piston volume which is arranged to receive a piston rod and along which the piston extends and retracts axially. The piston volume is in sealed hydraulic communication with the hollow rod volume to form a first volume which changes size as the piston moves along the piston rod whereby the application of hydraulic pressure to the first volume biases the piston towards its extended position. The hammer includes a bore and a collar. The collar forms an outer piston having a working surface which when exposed to hydraulic fluid has sufficient surface area to lift the piston and the drop weight.

The present invention relates to a hydraulic percussion device and a construction apparatus having the same, the hydraulic percussion device comprising: a cylinder; a piston; a backward port connecting a front chamber of the cylinder to a hydraulic source; a forward port formed on a rear chamber of the cylinder; a forward/backward valve for controlling the forward and backward movement of the piston; a control line for moving the forward/backward valve to a forward-movement location; a long-stroke port formed between the forward port and the backward port; a short-stroke port formed between the backward port on the cylinder and the long-stroke port; a shift valve disposed between the short-stroke port and the control line; a proximity sensor for detecting a bottom dead point of the piston upon the stroke on an object; and a controller for determining a striking condition on the basis of the detected bottom dead point, and transmitting a control signal to the shift valve.

The present invention relates to a hydraulic percussion device and a construction apparatus having the same, the hydraulic percussion device comprising: a cylinder; a piston; a backward port connecting a front chamber of the cylinder to a hydraulic source; a forward port formed on a rear chamber of the cylinder; a forward/backward valve for controlling the forward and backward movement of the piston; a control line for moving the forward/backward valve to a forward-movement location; a long-stroke port formed between the forward port and the backward port; a short-stroke port formed between the backward port on the cylinder and the long-stroke port; a shift valve disposed between the short-stroke port and the control line; a proximity sensor for detecting a bottom dead point of the piston upon the stroke on an object; and a controller for determining a striking condition on the basis of the detected bottom dead point, and transmitting a control signal to the shift valve.

A method of recognizing obstacles on operation of a vibratory pile driver of a work machine includes monitoring an acceleration signal of the vibratory pile driver during operation of the vibratory pile operator and analyzing the acceleration signal to determine the presence of an obstacle. The acceleration signal may be monitored over a time period which is determined based on an excitation frequency of the vibratory pile driver. The analysis may include comparing negative and positive half-waves of the acceleration signal. Responsive to the analysis indicating an obstacle, a system operator may be alerted, and/or operation of the vibratory pile driver may be adjusted via controller intervention.

A method of recognizing obstacles on operation of a vibratory pile driver of a work machine includes monitoring an acceleration signal of the vibratory pile driver during operation of the vibratory pile operator and analyzing the acceleration signal to determine the presence of an obstacle. The acceleration signal may be monitored over a time period which is determined based on an excitation frequency of the vibratory pile driver. The analysis may include comparing negative and positive half-waves of the acceleration signal. Responsive to the analysis indicating an obstacle, a system operator may be alerted, and/or operation of the vibratory pile driver may be adjusted via controller intervention.

A device and a method for generating percussive pulses or vibrations for a construction machine, in which a piston is reversibly reciprocated in a working space in a housing between a first reversal point and a second reversal point, wherein, for the purpose of generating the percussive pulses or vibrations, the piston is set into a reversible movement by a pressure fluid and the pressure fluid is led into and out of the working space in the region of the first reversal point and the second reversal point. The position of the piston is detected by way of a sensor, in that depending on the detected position of the piston a control unit controls at least one controllable valve, through which pressure fluid is led into and/or out of the working space, wherein by the control unit the movement of the piston is controlled.

A device and a method for generating percussive pulses or vibrations for a construction machine, in which a piston is reversibly reciprocated in a working space in a housing between a first reversal point and a second reversal point, wherein, for the purpose of generating the percussive pulses or vibrations, the piston is set into a reversible movement by a pressure fluid and the pressure fluid is led into and out of the working space in the region of the first reversal point and the second reversal point. The position of the piston is detected by way of a sensor, in that depending on the detected position of the piston a control unit controls at least one controllable valve, through which pressure fluid is led into and/or out of the working space, wherein by the control unit the movement of the piston is controlled.

Disclosed embodiments include post driving implements which attach to a power machine such as a loader in order to pick up posts of various sizes and materials and/or to drive the posts into the ground. In some exemplary disclosed embodiments, the post driving implement allows a post to be picked up when positioned inline with a direction of power machine travel and allows the post to rotate under the force of gravity to a second position in which the post is inline with a pounding mechanism for pounding the post into the ground. Catch mechanisms can be included to capture a portion of the implement to maintain the post in the second position until a release action is taken or a release command is given.

Disclosed embodiments include post driving implements which attach to a power machine such as a loader in order to pick up posts of various sizes and materials and/or to drive the posts into the ground. In some exemplary disclosed embodiments, the post driving implement allows a post to be picked up when positioned inline with a direction of power machine travel and allows the post to rotate under the force of gravity to a second position in which the post is inline with a pounding mechanism for pounding the post into the ground. Catch mechanisms can be included to capture a portion of the implement to maintain the post in the second position until a release action is taken or a release command is given.

A pile support device for a pile driver is disclosed. The pile support device can include a stationary pile guide operable to couple with a stationary portion of a pile driver. The pile support device can also include a pile holder coupled to the stationary pile guide. The pile holder can have a pile interface portion operable to interface with and support a pile while the pile is driven. The pile interface portion can be elevated above a ground surface and the pile can be exposed between the pile interface portion and the ground surface