Copyright © 2015 M W SHAW & SONS
HYDRASTUMPER TECHNICAL INFORMATION
The size and power of the Tractor used to mount a Hydrastumper on, is not in itself an important consideration, any size of Tractor could in theory be used. What needs to be considered is the payload capacity of the Tractor and the Speed of Operation you are expecting.
A Hydrastumper 35 is approximately 750Kg and the Hydrastumper 50 is approximately 1,000 Kg, hence your tractor needs to be able to carry the weight of the machine plus the weight of the tree, if you intend to move the tree any distance. You should also remember front-end weights may be required. From experience we would recommend a Tractor of 35-50 HP for the HS-35 and 70 HP for the HS-50.
There are a number of ‘Tree Extractors’ on the market, some even claim to be heavy duty; a number featured in You Tube videos use a scissor jaw design. The downside is that they have no independent lifting capacity, instead relying on the machine carrying them for lift, this means the break out force is limited by the lifting tonnage of the machine.
In addition to the average lifting limit of about three tonnes, the stress on the tyres is enormous when done continuously and because of the distance of the ‘arms’ from the machine, the lifting capacity is always less than the capacity of the machine.
The Hydrastumper was designed to take the lifting load off the tractor wheels during the extraction process with 28 tons of breakout lifting force from 2 Rams at 14 tons of pressure per Ram.
The Hydrastumper normally runs off the Tipping trailer hydraulic connector [External Hydraulic System] and only needs a return pipe fitted, which can be through the filler cap.
The fastest way to operate the machine is to use the "Power Pack" which consists of a pump mounted directly onto the tractor PTO spline, the pump has a mechanical gearbox giving it a 3:1 ratio and therefore operates at 3 x 540 RPM = 1620.
The circuit pressure generated is 2,250 lbs per Sq. Inch and with 4” Rams that amounts to 14 Tons of pressure per Ram.
A little difficult to answer as this depends greatly on the drivers skill in manoeuvring the tractor and operating the machine.
From experience and feedback from customers we would suggest in you could exceed 100 complete trees per hour, providing any obstructing limbs have been cut off, the same figure would apply for roots with visible stumps.
On good terrain we frequently hear reports of daily averages of 60 - 70 trees per hour and the Unofficial Record is 138 trees in an hour.
A major German customer gave us the following feedback which they use to calculate the clearance of “Cider” Apple trees, up to 30 cm in diameter:
14 Hours at 60 trees per hour = 840 tree per machine per day.
500 Hectares = 2000 trees. Or: 1 million trees in 60 days. They operate 20 machines and clear 16 - 17,000 trees per day.
NO significant problems have been experienced as a result of soil types, in fact soils types we expected to have problems with turned out to be ideal. Performance does increase with sandy soils.
Root breakage in heavy soils has not been a problem, the Hydrastumper tends to either pull roots out in the direction they grew, and they have their maximum tensile strength in that direction, or lifts the tree with the roots and surrounding soil in one lump, which if left is "cleaned" by the elements.
Experiments are in progress to test the efficiency of a vibrator mounted on the sub-frame to shake off soil adhering to the root system. This comprises of a vibrator shaft, belt driven by a hydraulic motor which is controlled by a third section added to the machine control valve.
M. W. SHAW & SONS
CHURCH FARM WORKS, COUGHTON FIELDS LANE
COUGHTON, NR. ALCESTER, WARWICKSHIRE, UNITED KINGDOM B49 6BS
Tel: 01789 763453 Fax: 01789 400451 Email: firstname.lastname@example.org