Patent Description:
A remote-controlled demolition robot can be equipped with various types of tool for demolition. For example, the demolition robot can carry a cut-off saw tool with a rotatable blade or saw blade for cutting steel and other materials in various forms. The saw blade of the cut-off saw is a consumption material that is worn and must be replaced when it is used up, whereupon the saw blade is typically replaced manually by the operator. In dangerous work environments, where the demolition robot is often be used, it can, however, be very inopportune for the operator to be in the immediate proximity of the work area of the demolition robot. This problem arises e.g. when the demolition robot is used in environments or surroundings, where radioactive radiation or dangerous gases belong to the risk picture. In the environments where the levels of radioactive radiation are so high that there is a risk that the operator is exposed to hazard or that the accumulated dose of radiation to which the operator can be exposed exceeds permitted levels, difficulties arise to manually perform exchange of the saw blade of the cut-saw tool in an efficient manner. <CIT> discloses a demolition robot with the features of the preamble of claim <NUM>.

The present invention is intended to obtain a remote-controllable demolition robot, which comprises a cut-saw tool with an exchangeable saw blade, which can reliably and automatically replace the rotatable saw blade without the operator having to perform manual actions, in order to improve safety and reduce work environment risks for the operator.

According to the invention, this purpose is resolved by a demolition robot having the features and characteristics stated in claim <NUM>. This object is also obtained with a method for remote-controlled automatic exchange of the saw blade on the saw tool associated with a demolition robot with features and characteristics according to claim <NUM>.

The invention means that worn components associated with a saw tool carried by a remote-controlled demolition robot can be replaced by new components in a remote-controlled, automatic and reliable manner without manual efforts by the operator, who then does not have to be exposed to e.g. radioactivity or dangerous gases in a risky work environment, when the demolition robot is operating. A detailed description of the invention follows below, from which further advantages appear.

In the following, a demolition robot according to the invention is described, wherein;.

<FIG> shows a remote-controlled demolition robot <NUM> with a saw tool <NUM> carried by a free end of a manoeuvrable robot arm <NUM> associated with the demolition robot. An operator walks beside the demolition robot and remote-controls it via a radio link by means of a portable operation cabinet equipped with the required joysticks and regulator.

<FIG> illustrate the demolition robot's robot arm <NUM> carrying a cut-off saw tool <NUM> with an exchangeable rotatable saw blade <NUM>. The saw blade is typically a disc-shaped rotationally symmetrical saw blade with a hub <NUM> configured to be releasably mounted on an end portion <NUM> associated with the rotatable spindle <NUM> of the cut-off saw tool. The saw blade <NUM> with the hub <NUM> is releasably arranged on the spindle end portion <NUM> with a torque-transmitting connection <NUM>. A release mechanism <NUM> for remote-controllable automatic exchange of the saw blade is arranged on the robot arm <NUM>. The release mechanism <NUM>, comprising a remote-controllable hydraulic cylinder, is arranged on the robot arm adjacent to the spindle and on the same side as the spindle relative to the saw blade.

The saw blade hub <NUM> has a first end connected with the saw blade <NUM>, a hub flange <NUM> connected with the saw blade <NUM> and a second end <NUM> facing the spindle <NUM>. The second hub end <NUM> has the shape of a truncated cone with an outer conical envelope surface <NUM> with a decreasing diameter in the direction from the saw blade <NUM> and a plane end surface <NUM> in the radial plane.

<FIG> shows that the hub end <NUM> is configured as an annular end portion <NUM>, the outer conical envelope surface <NUM> of which is configured to cooperate shape-wise with an inner conical clamping surface <NUM> associated with the spindle, and wherein the hub end surface <NUM> abuts and shape-wise cooperates with an inner bearing surface <NUM> associated with the spindle at insertion of the hub <NUM> in the spindle end portion <NUM> to obtain a radially as well as axially correct position of the saw blade on the spindle.

The saw blade hub has a central longitudinal opening <NUM>, extending between the ends of the hub and having an inner limitation surface <NUM> with varying cross sections. The annular end portion <NUM> has a bearing surface <NUM> facing the rotational axis and configured to abut against an intermediate piece <NUM> associated with a blocking element <NUM>, wherein the longitudinal opening <NUM> has a first inner diameter d1 along the bearing surface <NUM>. The inner limitation surface <NUM> is enlarged in the radial direction within the second hub end <NUM> and forms an axially extended inner cavity <NUM> with a second inner diameter d2, which is larger than d1. In the cavity <NUM>, the inner limitation surface <NUM> is adjacent to the bearing surface <NUM>, the saw blade hub has an internally arranged conically shaped inner engagement surface <NUM>, which is circumferential and configured with increasing diameter towards the saw blade. The engagement surface <NUM> of the hub is configured to cooperate with a blocking element <NUM> via inverse engagement, so that the saw blade <NUM> can releasably be retained on the spindle <NUM> under the influence of an applied tension force, for instance generated by a drive spring <NUM> that clamps the hub of the saw blade fixedly against the end of the spindle. The longitudinal opening <NUM> and inner cavity <NUM> of the hub are arranged to receive the blocking element <NUM> with a corresponding plurality of pawls <NUM> as well as a manoeuvring sleeve <NUM>, wherein the blocking element <NUM> is adapted to be inserted through the longitudinal opening <NUM> ending at the second end <NUM> of the hub and to extend into the cavity <NUM> to couple together the hub of the saw blade with the spindle.

The cut-off saw tool has a rotatable spindle <NUM>, which is mounted in a bearing housing <NUM> arranged on the robot arm. The spindle has a first end <NUM> that protrudes from the bearing housing and is arranged adjacent to the hub <NUM>. The first end <NUM> of the spindle has a first impact surface <NUM> in the radial plane (i.e. perpendicular to the rotational axis of the spindle), which is arranged to abut against the flange <NUM> associated with the hub as well as a receiving portion <NUM>, which is configured as a notch at the spindle end <NUM>. The receiving portion <NUM> has an inner conical clamping surface <NUM> connected with the impact surface <NUM> and an inner plane bearing surface <NUM> in the radial plane, which surrounds a central opening <NUM>. The conical clamping surface <NUM> of the spindle is configured for receiving the hub of the saw blade and shape-wise cooperating with the outer conical envelope surface <NUM> associated with the hub and forming the torque-transmitting connection <NUM> configured as a conical clamping connection, which during operation of the cut-off saw tool transmits the emerging torque from the spindle to the blade.

The spindle <NUM> comprises at least two rotationally symmetrical cavities <NUM>,<NUM> arranged internally and separated by a partition wall <NUM>, which includes a through-going central drilled hole <NUM> arranged along the rotational axis of the spindle, wherein the central opening <NUM> leads to the first cavity <NUM>.

The first cavity <NUM> is intended to receive the sleeve-like blocking element <NUM> and has an inner limitation surface with varying form and cross section, which shape-wise corresponds to the configuration of the blocking element in order to, by rotational driving, retain the blocking element <NUM>, which is integrated in the spindle and rotatable with the spindle. The cavity comprises a passage <NUM> with a reduced diameter connected to the receiving portion <NUM>. The passage is arranged for receiving an intermediate piece <NUM> associated with the blocking element <NUM>. The passage <NUM> is enlarged to an internal compartment arranged for receiving a rear end <NUM> of the blocking means. The internal compartment has an inner conical impact surface <NUM> intended to abut against the rear blocking means <NUM> of the blocking element. Adjacent to the partition wall <NUM>, the first cavity <NUM> has a cylindrical compartment with a reduced cross section in comparison with the cross section of the internal compartment arranged for accommodating the rear end of the blocking element. The cylindrical compartment is configured for accommodating a compression spring <NUM> with as associated casing. The second cavity <NUM> closest to the second end of the spindle is cylindrical with a uniform cross section, wherein a tension spring <NUM> is arranged, which is connected with a pulling rod <NUM>.

The spindle has a second end <NUM> connected with the transmission, a belt pulley <NUM>. The belt pulley is connected with a belt to a driving motor (not shown in the figure), so that the torque from the driving motor is transferred via the belt to the belt pulley <NUM>, which is mounted on the spindle <NUM>, so that the spindle is caused to rotate. The second end <NUM> of the spindle is facing a remote-controllable hydraulic cylinder <NUM>, which is arranged to activate a release of the saw blade, when automatic exchange of the saw blade is to be executed.

<FIG> shows the sleeve-like blocking element <NUM>, which has a first end with a plurality of radially outwardly directed pawls <NUM> arranged around the circumference, and which are resiliently and radially manoeuvrable, and a second annular end with a least one radially outwardly directed rear blocking means <NUM> as well as an intermediate piece <NUM> that connects the first and the second end. The blocking element <NUM> is integrated in the spindle by being partially arranged within the first cavity <NUM> of the spindle.

The blocking element has an axially directed central feed-through opening <NUM>, in which a manoeuvring means <NUM> coupled to the manoeuvring sleeve <NUM> is inserted, whereby the manoeuvring sleeve <NUM> projects from the feed-through opening in the longitudinal cavity of the hub towards the saw blade.

The rear blocking means <NUM> of the blocking element has an abutment surface that shape-wise cooperates with the cavity's inner conical impact surface <NUM> arranged in the internal compartment of the cavity and part of the intermediate piece <NUM> of the blocking element is arranged in the passage <NUM>. The first end of the blocking element carrying the pawls <NUM> protrudes from the central opening <NUM> of the spindle to the receiving portion <NUM> of the spindle, so that the pawls <NUM> are arranged in an axial position between the inner bearing surface <NUM> of the spindle and the first impact surface <NUM>. As shown in <FIG>, the blocking element is inserted through the longitudinal opening <NUM> of the hub to the enlarged inner cavity <NUM> at the second end <NUM> of the hub when a saw blade hub is inserted in the receiving portion <NUM> of the spindle. Together with the manoeuvring sleeve <NUM>, the function of the blocking element <NUM> is to couple the saw blade hub with the spindle <NUM> in a locked state, both radially and axially in a functional and reliable manner and block, prevent the saw blade hub <NUM> from being released from the spindle. The radially outwardly directed pawls <NUM> are resiliently and radially manoeuvrable and configured to engage with and capture the inner conical engagement surface of the hub. The manoeuvring sleeve is arranged, in an activated state, a locked state, to operate the blocking element <NUM> to releasably retain the saw blade hub by pressing the pawls radially outwards for engagement with the engagement surface <NUM> of the hub and thereby releasably retain the saw blade hub <NUM> against the spindle.

The blocking element <NUM> and the manoeuvring sleeve <NUM> thereby apply a clamping force against the hub's inner engagement surface <NUM>, which releasably clamps the saw blade hub <NUM> fixedly against the spindle <NUM> under the influence of a tension force along the manoeuvring means <NUM> for example generated by a tension spring <NUM>, whereby a conical torque-transmitting clamping connection <NUM> is formed between the inner conical clamping surface <NUM> of the spindle and the outer conical envelope surface <NUM> of the hub.

Thereby it is obtained that the saw blade <NUM> is releasably locked on the spindle with the torque-transmitting conical clamping connection <NUM> between the saw blade hub <NUM> and the spindle <NUM> in combination with the engagement surface <NUM> of the hub being captured by the pawls <NUM> and through inverse engagement of the hub end <NUM> around the blocking element <NUM> by the influence of a tension spring <NUM> or hydraulic cylinder <NUM>, whereby the hub of the saw blade is connected by being clamped fixedly against the spindle.

<FIG> further show that the demolition robot comprises a release mechanism <NUM> for releasing or freeing the rotatable saw blade in a remote-controllable automatic exchange of the saw blade by the operator. The release mechanism comprises a remote-controllable hydraulic cylinder <NUM> arranged on the robot arm <NUM>, a manoeuvring means <NUM> displaceably arranged on the spindle and a manoeuvring sleeve <NUM>. The hydraulic cylinder is coupled to the manoeuvring sleeve <NUM> via the displaceable manoeuvring means.

The manoeuvring means <NUM> consists of an elongated pulling rod coupled to the hydraulic piston of the hydraulic cylinder and extends along the rotational axis of the spindle through the cavity <NUM>,<NUM> of the spindle and through the drilled hole <NUM> of the partition wall, whereby the end facing the saw blade is coupled to the manoeuvring sleeve <NUM>. The manoeuvring means is preferably inserted in a central opening <NUM> in the manoeuvring sleeve and thereby coupled to the manoeuvring sleeve. The manoeuvring means <NUM> is displaceably accommodated in the spindle along the rotational axis of the spindle to enable the execution of an automatic exchange of the saw blade. A tension spring <NUM> arranged in the second cavity <NUM> of the spindle is connected to the manoeuvring means to apply a tension force on the manoeuvring means <NUM> and the manoeuvring sleeve <NUM> to maintain the torque-transmitting conical clamping connection <NUM> during operation.

<FIG> further show that the end <NUM> of the spindle is coaxially arranged with the hub <NUM> and end <NUM> of the saw blade, the blocking element <NUM>, the manoeuvring sleeve <NUM> and the manoeuvring means, whereby the blocking element further is coaxially arranged around the manoeuvring sleeve <NUM>, so that the blocking element <NUM> is arranged between the inner limitation surface <NUM> of the hub and the manoeuvring sleeve. Thereby a compact and reliable release mechanism is obtained.

<FIG> show that the manoeuvring sleeve <NUM> is arranged in the blocking element in the inner cavity of the spindle and has a first end <NUM> protruding towards the saw blade in the longitudinal opening <NUM> of the hub, and a second end <NUM>, which is coaxially arranged and slidably displaceable in the feed-through opening <NUM> of the blocking element and is coupled to the manoeuvring means <NUM> as well as an intermediate piece <NUM>, which connects the first and second ends of the manoeuvring sleeve. The manoeuvring sleeve has a longitudinal central opening <NUM> between the ends for receiving the manoeuvring means <NUM>. The manoeuvring sleeve is cylindrical with a varying outer cross section, whereby the first end <NUM> has a larger diameter than the second end <NUM>. The outer diameter of the first end is smaller than the inner diameter d1 of the hub to enable that the manoeuvring sleeve can be displaced out through the longitudinal opening <NUM> of the hub for picking an unused saw blade.

The intermediate piece <NUM> of the manoeuvring sleeve is configured with an arched comb surface <NUM>, arranged externally around the circumference, with a diameter that increases towards the saw blade, and which passes into a straight cylindrical surface along the first end. The manoeuvring sleeve is displaceably accommodated within the blocking element <NUM> and is displaceable through the longitudinal opening <NUM> of the hub. Through here, the manoeuvring sleeve can assume an activated state, a locking state, whereby the saw blade hub is caused to be releasably locked on the spindle or a deactivating release state, whereby the saw blade hub is caused to be released from the spindle.

The comb surface <NUM> is arranged so that at displacement of the manoeuvring sleeve towards the spindle <NUM> under the influence of a tension force from the tension spring <NUM> to a first state, locking state, it can operate or press the pawls to be displaced in radially outward direction and lock them against the inner engagement surface <NUM> of the hub. In the locking state, the comb surface <NUM> acts actively for the radially resilient pawls <NUM> not to move radially inwards towards the rotational axis. By remote-controlled activation of the release mechanism and the hydraulic cylinder, the manoeuvring sleeve <NUM> is caused to be displaced or pressed forward through the blocking element <NUM> and the saw blade hub <NUM> towards the saw blade <NUM> under the influence of the hydraulic cylinder in order to assume a second state, a release state. Thereby the pawls <NUM> of the blocking element is caused to be released from the engagement surface <NUM>, and the resilient pawls are caused to be radially displaced towards the rotational axis out of engagement with the hub, whereby the saw blade hub <NUM> is releasable and comes loose from the spindle <NUM>.

The release mechanism <NUM> further comprises a remote-controllable hydraulic cylinder <NUM> arranged on the robot arm in connection with the spindle, adjacent to the second end <NUM> of the spindle. The hydraulic cylinder is coupled to the manoeuvring sleeve <NUM> via the manoeuvring means <NUM>. The hydraulic cylinder has a hydraulic piston, which can be single-acting or double-acting. The hydraulic cylinder can be activated via remote-control by the operator, so that automatic exchange of the saw blade is executed. When activating the release mechanism <NUM> by means of remote activation, the hydraulic piston in the hydraulic cylinder <NUM> is displaced, wherein the manoeuvring means <NUM> and the manoeuvring sleeve <NUM> are pressed to be displaced axially along the rotational axis towards the saw blade, wherein automatic release of the saw blade is executed, whereupon a new unused saw blade is picked and automatically attached to the spindle.

A remote-controlled automatic exchange of saw blade on the saw tool arranged on the robot arm is executed according to a method, whereby a release mechanism <NUM> arranged on the robot arm <NUM> of the demolition robot is activated, and the torque-transmitting connection <NUM> between the spindle and the saw blade hub is released with the release mechanism. The used saw blade <NUM> is released with the release mechanism <NUM> from the spindle <NUM> and falls down, whereupon an unused saw blade <NUM>' is picked with the end portion <NUM> of the spindle out of a cassette <NUM>, containing at least one unused saw blade <NUM>'. The picked saw blade <NUM>' is attached and releasably locked with a torque-transmitting connection <NUM> to the end portion <NUM> of the spindle.

The release mechanism <NUM> is activated e.g. via remote control and activation of the hydraulic cylinder <NUM> for action on the manoeuvring sleeve <NUM> for release of the torque-transmitting connection <NUM> by the activated hydraulic cylinder displacing the manoeuvring sleeve <NUM> towards the saw blade <NUM>.

At exchange of the saw blade, the manoeuvring means <NUM> is by means of the hydraulic cylinder <NUM> pressed outwards towards the hub <NUM>. This results in the pawls <NUM> being displaced out of engagement against the conical engagement surface <NUM> in the hub and allows the blade <NUM> to fall out of the receiving portion of the spindle. A new blade <NUM>' is picked up from a pre-assembled cassette <NUM> and is locked e.g. by the hydraulic pressure on the hydraulic cylinder being drained to a tank or under the influence of the tension spring <NUM>.

The picked unused saw blade <NUM>' is releasably locked with the torque-transmitting connection <NUM> to the end portion <NUM> of the spindle by a plurality of pawls <NUM> associated with the blocking element <NUM> cooperating and forming an inverse engagement with a conically shaped engagement surface <NUM> associated with the saw blade hub <NUM> under the influence of the tension spring <NUM> and/or the hydraulic cylinder <NUM>.

Claim 1:
A demolition robot (<NUM>), comprising a robot arm (<NUM>) with a saw tool (<NUM>) with an exchangeable saw blade (<NUM>), wherein the saw tool comprises a rotatable spindle (<NUM>) with an end portion (<NUM>) and the saw blade, comprises a hub (<NUM>), wherein the saw blade hub is arranged on the end portion (<NUM>) of the spindle with a torque-transmitting connection (<NUM>), characterized in that a release mechanism (<NUM>) for automatic exchange of the saw blade (<NUM>) is arranged on the robot arm (<NUM>), wherein the release mechanism (<NUM>) comprises a remote-controllable hydraulic cylinder (<NUM>) arranged on the robot arm and a manoeuvring sleeve (<NUM>) coupled to the hydraulic cylinder via a displaceable manoeuvring means (<NUM>) arranged in the spindle (<NUM>), and the torque-transmitting connection (<NUM>) is configured as a conical connection, comprising an outer conical envelope surface (<NUM>) associated with the hub and an inner conical clamping surface (<NUM>) associated with the spindle,
wherein the manoeuvring sleeve (<NUM>) is arranged to cooperate with a blocking element (<NUM>) integrated in the spindle (<NUM>),
wherein the blocking element (<NUM>), has a first end with a plurality of radially outwardly directed pawls (<NUM>) arranged around the circumference, and which are resilient and manoeuvrable in radially outward direction and configured to engage with and capture an inner conical engagement surface (<NUM>) of the hub,
wherein in a locking state the manoeuvring sleeve is arranged to operate the blocking element (<NUM>) under the influence of a tension force along the manoeuvring means (<NUM>) wherein the blocking element (<NUM>) in a locking state is arranged to releasably retain the saw blade hub (<NUM>), by pressing the pawls (<NUM>) radially outwards for engagement with the engagement surface (<NUM>) of the hub,
wherein in a release state, the hydraulic cylinder is activated, and the manoeuvring sleeve (<NUM>) is caused to be displaced or pressed forward through the blocking element (<NUM>) and the saw blade hub (<NUM>) towards the saw blade (<NUM>),
under the influence of the hydraulic cylinder, wherein the blocking element is caused to release the hub (<NUM>) under the influence of the manoeuvring sleeve, and the saw blade hub (<NUM>) is caused to be released from the end portion (<NUM>) of the spindle, wherein the saw blade comes loose from the spindle (<NUM>).