Sandvik Mining and Construction Oy

Sandvik Tamrock Oy

Sandvik Aktiebolag

Sandvik Mining and Construction Tools Ab

Sahdvik Tamrock Oy

Jorma Mäki

Markku Keskiniva

Erkki Ahola

Mauri Esko

Aimo Helin

Timo Muuttonen

Antti Koskimäki

Juha Piispanen

Olivier Bruandet

Esa Rantala

Timo Kiikka, Deceased

Esko Mauri

A down the hole drilling assembly has a top end coupled to a drill string and a bottom cutting end. The drilling assembly includes a piston arranged moveably inside a casing with a piston nose positioned at an axially bottom end and a top working chamber at a top end, a bottom working chamber at the bottom end, a driver sub having axially extending driver sub splines on an internal surface, a drill bit having an axially extending central bore including an elongate shank provided with axially extending shank splines on its outer surface for engagement with the driver sub splines to form a spline area, a guide sleeve forming a seal with the piston nose, the guide sleeve having an inner and outer surface, and at least one air passageway extending through the guide sleeve for fluidly connecting the bottom chamber to the spline area to provide lubrication thereto.

Spline lubrication for DTH hammers

A pressure fluid operated impact device comprising a frame () whereto a tool () is mountable movably in its longitudinal direction, and control means () for controlling pressure fluid feed to the impact device (), as well as a method of generating a stress pulse in a pressure fluid operated impact device. The impact device () comprises a working chamber () and a transmission piston () moving therein. Energy charging means for charging energy of pressure fluid and the control means are coupled to allow periodically alternately pressure fluid to flow to the working chamber () and, correspondingly, to discharge pressure fluid from the working chamber (). In the method, pressure fluid is fed to the working chamber (), which produces a force pushing the transmission piston () in the direction of the tool (), thus generating a stress pulse in the tool ().

Impact device and method for generating stress pulse therein

A method for controlling the operation of a pressure fluid operated percussion device and to a pressure fluid operated percussion device. The method includes influencing the shape of a stress wave by setting a suitable clearance between a transmission piston and a tool. The percussion device is provided with a device for setting the clearance between the transmission piston and the tool.

Percussion device

The invention relates to a method for breaking rock to be drilled in rock drilling, in which method the rock to be drilled is subjected to successive stress pulses via a tool. The method comprises stress pulses being exerted on the rock at a high frequency, and the load proportion calculated on the basis of the values of the frequency and the length (t) of the stress wave being at least 0.075.

Method for breaking rock

A pressure-fluid-operated percussion device includes a frame allowing a tool to be arranged movably in its longitudinal direction. Pressure liquid is fed to the percussion device and returned to a pressure liquid tank. A stress pulse is produced in the tool utilizing pressure of the pressure liquid. A pressure liquid source maintains pressure in the working pressure chamber. Pressure liquid is intermittently fed to the percussion device such that the pressure liquid pushes a transmission piston into a predetermined backward position. Pressure liquid is alternately discharged rapidly from the percussion device so that the pressure of the pressure liquid in the working pressure chamber and the pressure liquid flowing from the pressure liquid source pushes the transmission piston towards the tool, generating a stress pulse in the tool.

Pressure-fluid-operated percussion device

The invention relates to a method for controlling a pressure fluid operated percussion device comprising a working chamber for pressure fluid and in the working chamber a transmission piston installed movably with respect thereto so as to enable a tool installed in the percussion device to be pressed against a material to be broken in order to generate a stress pulse, and to a percussion device. The method comprises adjusting the length of the stress pulse by adjusting the time during which pressure influences the transmission piston. The percussion device comprises an adjustment element and adjustment means for adjusting the influence time of the pressure of the pressure fluid being fed via a control valve and influencing the transmission piston.

Method for controlling pressure fluid operated percussion device, and percussion device

The invention relates to a method and a rock drilling rig for drilling a hole in a rock. In the method the hole is drilled with a so-called top-hammer rock drilling rig including a drill rod and a cone roller bit at the end of the drill rod. During drilling with the percussion device, stress pulses of low amplitude are produced at a high frequency of at least 200 Hz. In the rock drilling rig, the cone roller bit () at the end of the drill rod and the percussion device are configured to feed stress pulses of low amplitude, at the frequency of at least 200 Hz, via the drill rod and the cone roller bit to the rock.

Method and rock drilling rig for hole drilling

A method and software product for controlling a percussion device belonging to a rock-drilling machine, and a percussion device. The impact frequency of the percussion device is set so that the percussion device forms a new compression stress wave to the tool always when reflected waves from the previous compression stress waves reach a first end of the tool. This requires that the impact frequency be set proportional to the propagation time of the stress wave, whereby the length of the used tool and the propagation velocity of the stress wave in the tool material are to be noted.

Method for controlling percussion device, software production, and percussion device

A method of generating a stress pulse, and an impact device. In the method, pressure fluid is fed as pressure pulses to a working chamber residing between the frame of the impact device and a tool such that the resulting force presses the tool towards the material to be processed. The impact device comprises a working chamber and device for conveying pressure fluid as pressure pulses thereto such that a force is produced between the frame of the impact device and a tool to press the tool towards the material to be processed.

Method of generating stress pulse in tool by means of pressure fluid operated impact device, and impact device

An impact device includes a frame to which a tool is connectible, and a stress element that is supported on the frame and disposed between the frame and the tool. A hydraulic control system leads pressurized hydraulic fluid into and out of a hydraulic fluid space such that the stress element causes a stress pulse in the tool. The hydraulic control system includes a rotatingly installed control valve that has control openings for intermittently leading the hydraulic fluid out from the hydraulic fluid space.

Impact device with a rotable control valve

The invention relates to a control valve, a percussion device and a method of controlling a working cycle of a percussion device. A percussion device () for breaking rock includes an impact element () controlled by a control valve (). The control valve includes a control element () arranged to control channels () leading to a working pressure surface () of the impact element (). The control element, during a working cycle of the control valve, is arranged to open and close pressure channels at several connecting moments so that during one working cycle of the valve, several impact pulses are arranged to be produced.

Control valve and a method for a percussion device with a working cycle involving several coupling moments

The invention relates to a control valve, a percussion device and a method of controlling a working cycle of a percussion device. The percussion device () used for breaking rock comprises an impact element (), which is controlled by a control valve (). The control valve comprises a control element (), which is arranged to control channels () leading to a working pressure surface () of the impact element (). The movement of the control element to its extreme position is arranged to form a closed pressure space, where pressure medium compresses and converts kinetic energy of the control element into pressure energy. The pressure energy is re-converted into kinetic energy and utilized when the control element changes its direction.

Control valve in a percussion device and a method comprising a closed pressure space at the end position of the piston

An impact device for a rock drill. The rock drill includes a tool and a mechanism for delivering a stress pulse to the tool. That mechanism includes an impact element supported to a frame of the drill, and a mechanism for subjecting the impact element to stress and thereafter releasing the impact element suddenly from the stress, whereupon stored stress energy in the impact element is discharged in the form of a stress pulse directed at the tool.

Impact device

During the drilling of rock by a rock drill bit, percussive impacts are applied to the drill bit by a reciprocating piston which impacts a shank that transmits the impacts to the drill bit. Secondary pistons are provided to push the shank forwardly in response to a pressure medium acting on rear surfaces of the secondary pistons. The secondary pistons push the shank to its optimum point of impact. During a drilling operation, as the piston applies percussive impacts, return pulses are reflected back to the secondary pistons. Pressure sensors detect the return pulses in the form of pressure pulses, which indicate whether the drill bit has encountered weaker or stronger materials. Based upon characteristics of the detected pressure pulses, the operation of the drilling machine, e.g., the feed and/or impact power thereof, is regulated, so that the shank is returned to its optimum point of contact.

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Mutala, Finland

Jorma Mäki