Tool holding arrangements for concrete surface processing equipment

Abstract

A tool driver for concrete surface processing equipment is disclosed. The tool driver is arranged to receive a tool holder, and to hold the tool holder in locked position by means of a locking member. In the locked position the tool driver and the tool holder are axially fixed in relation to each other by means of the locking member and together rotatable about the axis of rotation of the tool driver. Construction equipment comprising the tool driver, tool holder, and locking member are also discussed.

Description

[0001] TITLE

[0002] TOOL HOLDING ARRANGEMENTS FOR CONCRETE SURFACE PROCESSING EQUIPMENT

[0003] TECHNICAL FIELD

[0004] The present disclosure relates to tool holders and construction equipment for processing hard surfaces such as concrete and stone floors. There are disclosed improved tool drivers and tool holding arrangements for grinding and polishing machines.

[0005] BACKGROUND

[0006] Concrete surfaces are commonly used for flooring in both domestic and industrial facilities. The size of concrete surface floors ranges from a few square meters for a domestic garage floor to thousands of square meters in larger industrial facilities. Concrete surfaces offer a cost efficient and durable flooring alternative and have therefore gained popularity over recent years.

[0007] A floor grinder can be used to efficiently process a concrete surface in order to, e.g., obtain a level surface having a uniform topology and / or a surface having a desired surface texture. Floor grinders can also be used to polish concrete surface in order to obtain a glossy surface finish.

[0008] The grinding tools used by floor grinders come in various grit, and the same tool driver can often be used to drive more than one type of tool. A concrete surface processing operation often requires multiple changes of abrasive tools, either because the tools get worn down, or because a sequence of tool grits is required to obtain a desired end result.

[0009] The machine is often tilted when changing abrasive tools in order to expose the tool drivers underneath the machine. It is desired that the tools remain in place as the machine is tilted to expose the tools. US 2008 / 0072386, US 5,806,132 and EP 0 679 766 all disclose various tool holders for securing surface processing tools to a tool driver. However, further improvements are desired. In particular, there is a need for tool holding arrangements which are robust and resistant to wear from both dust and chemicals, and at the same time easy to use for an operator desiring to change abrasive tools.

[0010] SUMMARY

[0011] It is an objective of the present disclosure to provide improved tool holding arrangements for surface processing construction equipment such as floor grinding and polishing machines. This objective is at least in part obtained by a tool driver for concrete surface processing equipment. The tool driver is arranged to receive a tool holder from an outer end of the tool driver in an insertion direction along an axis of rotation of the tool driver, and to rotatably lock the tool holder in a received position. The tool driver comprises a central aperture with a side wall that extends in the direction of the axis of rotation. An annular groove is formed in at least a part of the side wall transversal to the axis of rotation. The side wall comprises one or more open slots extending axially from the outer end of the tool driver and past the annular groove. The annular groove is arranged to receive a locking member having a periphery that is matched to the annular groove. This locking member is configurable in an open position, in which position the tool holder can traverse the one or more open slots in the insertion direction past the annular groove and into the received position. The locking member is also configurable in a locked position, in which position the periphery of the locking member at least partly covers the open slots to prevent the tool holder from moving past the groove in direction opposite to the insertion direction. This way the tool driver is able to prevent a tool holder from falling off the tool driver. The locking member allows convenient locking and unlocking that allows the tool holder to be assembled with the tool driver and removed from the tool driver. The annular groove formed in the side wall and the periphery of the locking member preferably both extend in a plane transversal to the axis of rotation and preferably perpendicular to the axis of rotation. Radially inwards extending portions can be formed in the periphery of the locking member that are matched to the open slots. The locking member, when received in the annular groove, is rotatable about the axis of rotation from an open position where the radially inwards extending portions are aligned with the open slots, to a locked position where the periphery of the locking member at least partly covers the open slots.

[0012] The locking member may be formed as a spring ring or circlip with an annular periphery broken by the radially inwards extending portions. Hence, the locking member may be manufactured in a cost efficient manner. The locking member can for instance be formed from sheet metal or from metal wire, which are both cost effective options that allow the locking member to be mass-produced in an efficient manner.

[0013] The locking member, when received in the annular groove, is preferably biased in an outwards radial direction and compressible in an inwards radial direction. In other words, the locking member strives to expand radially, but is prevented from expanding by the bottom in the groove. This way friction between the locking member and the bottom of the groove prevents the locking member from moving inadvertently unless it is compressed to reduce the friction between the locking member and the bottom of the groove. The locking member may for instance comprise legs that are operable by hand to compress the locking member in the inwards radial direction. Handle portions of increased axial extension can also be formed on the legs of the locking member to facilitate manual compression of the locking member by an operator. An operator presses the leg portions together or in opposite directions, whereupon the locking member is compressed such that its radial extension decreases.

[0014] According to some aspects, at least one abutment is formed on the tool driver. The abutment is arranged to prevent rotation of the locking member past the locked position and / or past the open position. This way an operator is guided to the correct locking member positions for locking and releasing a tool holder. The locking member may comprise an axial protrusion arranged to cooperate with at least one abutment formed in the central aperture of the tool driver to prevent rotation of the locking member past the locked position and / or past the open position. The abutment can for instance be a discontinuity of the annular groove arranged to cooperate with a matching portion formed on the locking member. The locking member may also comprise a radial protrusion that extends out radially from the periphery of the locking member.

[0015] According to some aspects, the tool driver comprises one or more spring loaded elements, such as spring plungers, arranged to engage the locking member at respective predetermined positions to releasably hold the locking member in the open position and / or in the locked position. These spring loaded elements also guide the operator to let him or her know when the locking member is in the open position and / or in the locked position. The spring loaded elements also retain the locking member in the selected position, such that it does not inadvertently move away from the selected position.

[0016] The locking member optionally comprises a central hub portion with spokes extending radially outwards to peripheral portions matched to the annular groove, where the peripheral portions are configured to cover the open slots in a nominal position of the locking member. The peripheral portions are arranged to move in an inwards radial direction away from the open slots in response to a pressure applied to the central hub portion to allow the tool holder to traverse the one or more open slots in the insertion direction past the annular groove and into the received position. This locking member does not have to rotate to enter into the open position, which may be an advantage in some cases. Abutments can be arranged on the tool driver in direction radially inwards from the peripheral portions, where the abutments are arranged to prevent movement by the peripheral portions in the inwards radial direction by more than a predetermined distance. The abutments act as stops that prevent the peripheral portions from moving too far radially inwards. This reduces the need for the operator to push with just enough force on the central hub portion of the locking member. The annular groove may comprise sections of reduced radial depth matched to respective separations between the peripheral portions on the locking member, in order to prevent rotation by the locking member relative to the tool driver.

[0017] The objective is also at least in part obtained by a tool holder arranged to be received along an axis of rotation and held in position by a tool driver. The tool holder is arranged to hold one or more abrasive tools for processing a concrete surface. The tool holder has a central aperture with at least two radially inwards extending tongues arranged a distance below a tool plane of the tool holder.

[0018] According to some aspects a locking arrangement for a concrete surface processing equipment is provided comprising the tool driver, the tool holder and the locking member, wherein in the locked position the tool driver and the tool holder are axially fixed in relation to each other by means of the locking member and together rotatable about the axis of rotation of the tool driver.

[0019] Various types of construction equipment, grinding tool holders and production methods are also described herein. The machines, tools and methods are associated with the advantages mentioned above.

[0020] Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a / an / the element, apparatus, component, means, step, etc." are to be interpreted openly as referring to at least one instance of the element, apparatus, component, means, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated. Further features of, and advantages with, the present invention will become apparent when studying the appended claims and the following description. The skilled person realizes that different features of the present invention may be combined to create embodiments other than those described in the following, without departing from the scope of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present disclosure will now be described in more detail with reference to the appended drawings, where

[0022] Figures 1A-B illustrate an example floor grinder;

[0023] Figure 2 schematically shows a tool holding arrangement;

[0024] Figures 3A-E show an example tool driver in open position;

[0025] Figures 4A-B illustrate a tool holding arrangement in open position;

[0026] Figures 5A-D show an example tool driver in locked position;

[0027] Figure 6 illustrates a tool holding arrangement in locked position;

[0028] Figure 7 is a cross-section view of a tool holder in locked position;

[0029] Figure 8 schematically illustrates details of a tool driver;

[0030] Figures 9A-B schematically illustrates a locking member operation;

[0031] Figure 10 illustrates a tool driver with a rotation prevention abutment;

[0032] Figures 1 1 A-D illustrate a locking member operation;

[0033] Figures 12A-F show an assortment of example locking members;

[0034] Figures 13A-C show an alternative locking member; and

[0035] Figures 14A-B show an alternative tool driver with a locking member.

[0036] DETAILED DESCRIPTION

[0037] The invention will now be described more fully hereinafter with reference to the accompanying drawings, in which certain aspects of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments and aspects set forth herein; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout the description. It is to be understood that the present invention is not limited to the embodiments described herein and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the appended claims.

[0038] Figures 1A and 1 B illustrate an example floor grinder 100 for processing a concrete surface 101. The floor grinder 100 comprises a first electric motor 110 arranged to rotate a number of tool drivers about respective axes of rotation A. Each tool driver has a tool holder 120 attached to it onto which abrasive tools and / or polishing pads may be assembled. Some abrasive tools may also be directly attached to the tool drivers without an intermediate tool holder. Different tool holders can be used to hold different abrasive tools, such as tools of varying grit.

[0039] The tool holders 120 on the example machine 100 are comprised on a rotatable body section 130. This body section is often referred to as a planet. A second optional electric motor 115 is arranged to rotate the planet about a central axis 135. The type of drive system shown in Figures 1A-B is generally referred to as a planetary drive system.

[0040] Electrically powered floor grinders like that illustrated in Figures 1A-B are generally known. Floor grinders driven by combustion engines, such as propane-fueled combustion engines, are also known. The tools and techniques disclosed herein are applicable with both electrically powered and combustion engine machines.

[0041] The machine 100 can be used to grind, polish and / or to clean hard material surfaces such as concrete and stone surfaces. Depending on the desired surface processing operation to be performed, tools of varying grit are attached to the tool holders 120. When installing a new set of grinding tools, or replacing worn-out tools, the machine 100 is normally tilted backwards B, which exposes the tool holders 120.

[0042] During operation, the tools held by the tool holders 120 are fixed in position by the downwards pressure applied from the machine 100 in use and by a rotational locking arrangement of some kind. Various rotational locking arrangements are known in the art and will therefore not be discussed in detail herein. However, it is also desired that the tools remain in place as the machine is tilted backwards B. Hence, there is a need for an axial locking mechanism which prevents the tool holders from falling off when the machine is tilted backwards B, which allows for convenient tool replacement at the work site.

[0043] Figure 2 schematically shows a tool holding arrangement 200 that comprises a tool driver 210, a tool holder 220, and concrete surface processing tools 230. The tool driver 210 is attached to a drive shaft or other form of drive arrangement of the machine 100 in torque-transmitting manner such that it rotates the tool holder 220 and the tools 230 in use. The tool driver 210 is normally arranged to receive the tool holder 220 in an insertion direction I from an outer end 215 of the tool driver, which is the tool holder end facing the concrete surface 101 . The tool holder 220 is received along the axis of rotation A and is rotationally locked by the tool driver 210 in the received position, which means that the tool holder is prevented from rotating relative to the tool driver and thus also to the drive shaft. The rotational locking arrangement, however, does not prevent the tool holder 220 from moving axially with respect to the tool driver 210, in direction opposite to the insertion direction I, which means that the tool holder 220 may fall off the machine 100 when the machine is tilted backwards B to expose the tool holders 220.

[0044] It is desired to provide an axial locking arrangement that complements the rotational locking arrangement such that the tool holders stay in place even if the machine 100 is tilted backwards, or if the tool holders are exposed for some other reason, such as if the machine 100 moves over a hole in the concrete surface. This axial locking arrangement should preferably be easy to manage for an operator at the work site, even if the operator wears gloves, and should not require any special tools. The axial locking arrangement should also be insensitive to the harsh conditions encountered at many construction work sites, where dust, slurry and various concrete surface processing chemicals are common. It is proposed herein to use a resilient locking member such as a spring ring or circlip-like member to axially lock the tool holder 220 to the tool driver 210. This locking member is easy to operate, robust, and also cost efficient. Figures 3A- E and Figures 4A-B illustrate one example of this axial locking arrangement in its open position which is the position where the tool holder 220 can be assembled onto the tool driver 210. Figures 5A-D, Figure 6 and Figure 7 shows the same example axial locking arrangement in its locked position where the tool holder 220 is axially locked to the tool driver 210 such that it cannot fall off if the tool holder leaves the concrete surface, such as when the machine 100 is tilted backwards or when a hole in the concrete surface is encountered. Figures 13A-C and Figures 14A-B illustrate another example locking member.

[0045] The locking members disclosed herein can be manufactured and sold separately or together with corresponding tool drivers and / or tool holders.

[0046] The different locking members described herein are received in an annular groove formed in the tool driver and may be placed in an open position or in a locked position. The open position is a position of the locking member relative to the tool driver where the tool holder can be received by the tool driver, while the locked position is a position where the tool holder is prevented from moving axially in direction opposite to the insertion direction I, i.e., where it is prevented from falling off the tool driver when the machine 100 is tilted backwards B.

[0047] The tool drivers 210 according to the present disclosure comprise a central aperture 310 which may be cylindrical or formed in some other shape, with a side wall 320 that extends in the direction of the axis of the rotation A. The central aperture 310 may be a through-hole that extends axially through the tool driver from its outer end 215 to the opposite end, or a recess that does not extend all the way through the tool driver in the axial direction. In this example the tool driver 210 comprises three wings 21 1 that enter matching cut-outs in the tool holder 220 to rotationally lock the tool holder to the tool driver, however, other rotational locking mechanisms are also known. The wings 21 1 in the examples presented herein comprise countersunk bolt holes for attaching the tool driver 210 to the machine 100. An annular groove 330 is formed in at least a part of the side wall 320 as illustrated in, e.g., Figure 3A and Figure 5A, and also in Figure 14B. The side wall 320 also comprises one or more open slots 340 extending from the outer end 215 of the tool driver 210 in direction of the axis of the rotation A, i.e., in the insertion direction I, and past the annular groove 330.

[0048] The open slots 340 formed in the side wall 320 are configured to cooperate with radially inwards extending tongues 350 or other members with similar function formed on the tool holder 220. The radially inwards extending tongues 350 on the tool holder 220 are arranged a distance below a tool plane of the tool holder 220, such that the tongues 350 enter past the groove 330 in the insertion direction I into the received position. This is schematically illustrated in Figure 8, and also seen in the inserts in Figure 3A and Figure 5A. The tongues 350, having entered past the groove, can be axially locked by sliding the locking member into the locking position, as exemplified in Figure 5A. An alternative locking member that instead flexes to uncover the open slots will be discussed below in connection to Figures 13A-C and Figures 14A-B.

[0049] The annular groove 330 is, generally, arranged to receive and to rotatably hold a locking member 360 having a periphery 1210, 1350 matched to the annular groove 330. This means that the periphery 1210, 1350 of the locking member 360 is matched to the particular geometry of the annular groove 330. The locking member 360 is configurable in an open position 300 where the tool holder 220 can traverse the one or more open slots 340 in the insertion direction I past the annular groove 330 and into the received position. The locking member 360 is also configurable in a locked position 500 where the periphery 1210 of the locking member 360 at least partly covers the open slots 340 to prevent the tool holder 220 from moving in direction opposite to the insertion direction I. Thus, an operator wanting to assemble a tool holder 220 onto a tool driver 210 operates the locking member 360 to place it in the open position, where the tool holder 220 can be inserted in the insertion direction. The operator then operates the locking member to cover the open slots, thereby preventing the tool holder 220 from moving in the direction opposite to the insertion direction. The periphery 1210, 1350 of the locking member 360 and the annular groove 330 preferably extend in the plane P transversal to and preferably perpendicular to the axis of rotation A.

[0050] The locking member may be formed in many different ways. According to one example principle of operation, the locking member 360 has radially inwards extending portions 1220 formed in the periphery 1210 that are matched to the open slots 340, as illustrated in Figures 12A-F. According to these examples, the locking member 360, when received in the annular groove 330, is rotatable R about the axis of rotation A from an open position 300, 900 where the radially inwards extending portions 1220 are aligned with the open slots 340, to a locked position 500, 910 where the periphery 1210 of the locking member 360 at least partly covers the open slots 340. Figure 3A, Figures 3C-E, Figures 4A- B, and Figure 9A illustrate the locking member 360 in the open position while Figures 5A-D, Figures 6-7, and Figure 9B illustrate the locking member 360 in the locked position where the locking member extends above the radially inwards extending tongues 350 formed on the tool holder 220, thus preventing the tool holder 220 from moving axially past the groove 330.

[0051] The locking member 360 may for instance be a spring ring or circlip with an annular periphery 1210 broken by the radially inwards extending portions 1220, as illustrated by the various examples 1200-1205 in Figures 12A-F. In each of the examples 1200-1205 the locking member 360 comprises radially inwards extending portions 1220 formed in the periphery 1210 that are matched to the open slots 340, and legs 1230 operable by hand to compress the locking member 360 in the inwards radial direction Di. The legs may be covered by a soft or resilient material, such as a piece of rubber tube 380, as illustrated in Figure 3B. This soft material improves grip and makes handling the locking member more comfortable for an operator. A friction promoting material such as non-slip tape or the like can also be used to improve the grip of the operator. The example locking members illustrated in Figures 12A-F, when received in the annular groove 330, are biased in an outwards radial direction Do and compressible in an inwards radial direction Di, as shown in Figure 9A. This means that the locking members push outwards against the bottom of the groove which generates friction that hold the locking members in position. This friction reduces if the locking member is compressed radially inwards. Thus, the locking member can more easily be rotated when it is compressed. In the examples of Figures 12A-F, the legs 1230 are used to compress the locking member radially inwards. In The example shown in Figures 13A-B the locking member is instead compressed radially inwards by pushing on the central hub portion 1310 axially.

[0052] In the example 1200 the two legs 1230 are offset axially 1231 such that they can pass each other when the locking member is compressed in the radial direction by an operator wanting to place the tool driver 210 in the open position 300 where it can receive a tool holder 220. The locking members 360 in the examples 1200-1202 are formed in sheet metal. The locking members are in this case cut out from the sheet metal and then formed into locking members by rolling and / or pressing. The locking members 360 in the examples 1203-1205 are formed in wire. An advantage of forming the locking member in sheet metal is that handle portions 1232, 1234 can be formed on the legs with an increased axial extension 1232 to facilitate radial compression of the locking member by an operator, as shown in example 1202 and 1205. The legs of the wire locking members can be bent in the axial direction 1233 to facilitate radial compression of the locking member by an operator, as shown in example 1204. The legs 1230 of the wire locking members can also be formed as handles as in the example 1205.

[0053] The central aperture 310 in the tool driver 210 may comprise a ledge some way down in the axial direction where the side wall 320 has a section of reduced diameter after the annular groove 330 when seen from the outer end 215. This section of reduced diameter is arranged to support the locking member 360 in the axial direction. In the examples the central aperture 310 has a cylindrical shape, but other shapes are also possible, such as a hexagon cross-section shape or the like.

[0054] With reference to Figure 8, the annular groove 330 formed in the side wall 320 preferably extends in a plane P perpendicular to the axis of rotation A, although a groove with extension at an angle relative to the plane P is also possible. When the tool holder 220 is assembled with the tool driver 210, i.e., when the tool holder is inserted in the insertion direction I, the radially inwards extending tongues 350 formed on the tool holder 220 traverses past the groove 330, which allows the locking member 360 to rotate in the groove past the radially inwards extending tongues 350 formed on the tool holder 220, thereby axially locking the tool holder 220 to the tool driver 210.

[0055] According to some aspects the locking member 360 may only rotate along a predetermined angular span from one end point to another end point. The outer end point is then preferably associated with the open position and the second end point is associated with the locked position. This feature can be achieved in a number of different ways. Figures 3E and 5D illustrate a mechanism that prevents the locking member 360 from rotating past a first point in clockwise direction and past a second end point in counter-clockwise direction. Here a radial protrusion 365 has been formed on the locking member 360 that extends out radially from the locking member 360 as illustrated in, e.g., Figure 5D. The radial protrusion 365 abuts the tool driver at a first location 370 and at a second location 510 as illustrated in Figures 3E and 5D. The first location 370 is associated with the open position of the locking member and the second location 510 is associated with the locked position.

[0056] According to some aspects the tool driver 210 also comprises one or more spring loaded elements, such as spring plungers, arranged to engage the locking member at respective predetermined positions to releasably hold the locking member 360 in the open position and / or in the locked position. This prevents the locking member from inadvertently moving between the open and lock position. An operator also receives tactile feedback indicative of when the locking member has been placed in the open position and / or in the locked position.

[0057] With reference to Figure 10 and Figures 1 1A-D, an abutment 1010, 1020 can also be formed in the central aperture 310 of the tool driver 210 that prevents rotation of the locking member 360 past the locked position and / or past the open position. The locking member 360 then comprises a cooperating portion that engages the abutment or abutments at the end point or end points, such as an axial extension 1 1 10 formed on a leg of the locking member. The abutment may also be formed as a discontinuity of the annular groove 330.

[0058] Figures 13A-B and 14A-B illustrate an alternative axial locking mechanism. In this alternative the locking member 360 is resilient, i.e., flexible, and comprises a central hub portion 1310 with spokes 1320 extending radially outwards to peripheral portions 1330 that are configured to cover the open slots 340 in a nominal position of the locking member 360, as illustrated in Figures 14A-B. If pressure is applied to the central hub portion 1310, e.g., by the thumb of an operator, as illustrated by the arrow C in Figure 14B, then the locking member flexes whereupon the peripheral portions 1330 move in an inwards radial direction Di and away from the open slots 340, as illustrated in Figure 13C, which places the axial locking mechanism in its open position where the tool holder can be assembled with the tool driver or removed from the tool driver. Abutments 1410 are optionally arranged radially inwards from the peripheral portions 1330 to stop the peripheral portions from moving too far inwards when pressure is applied to the central hub portion 1310. The annular groove 330 may furthermore comprise sections of reduced radial depth matched to respective separations 1340 between the peripheral portions 1330 on the locking member 360 to prevent rotation by the locking member 360 about the axis A.

Claims

CLAIMS1 . A tool driver (210) for concrete surface processing equipment (100), where the tool driver (210) is arranged to receive a tool holder (220) from an outer end (215) of the tool driver in an insertion direction (I) along an axis of rotation (A) of the tool driver, and to rotatably lock the tool holder (220) in a received position, the tool driver (210) comprising a central aperture (310) with a side wall (320) extending in direction of the axis of rotation (A), where an annular groove (330) is formed in at least a part of the side wall (320) transversal to the axis of rotation (A), where the side wall (320) comprises one or more open slots (340) extending axially from the outer end (215) of the tool driver (210) past the annular groove (330), where the annular groove (330) is arranged to receive a locking member (360) having a periphery (1210, 1350) matched to the annular groove (330), where the locking member (360) is configurable in an open position (300), in which position the tool holder (220) can traverse the one or more open slots (340) in the insertion direction (I) past the annular groove (330) and into the received position, and where the locking member (360) is configurable in a locked position (500), in which position the periphery (1210) of the locking member (360) at least partly covers the open slots (340) to prevent the tool holder (220) from moving in direction opposite to the insertion direction (I).

2. The tool driver (210) according to claim 1 , where the annular groove (330) formed in the side wall (320) and the periphery (1210, 1350) of the locking member (360) extend in a plane (P) transversal to the axis of rotation (A) and preferably perpendicular to the axis of rotation (A).

3. The tool driver (210) according to claim 1 or 2, where radially inwards extending portions (1220) are formed in the periphery (1210) of the locking member (360) matched to the open slots (340), where the locking member (360), when received in the annular groove (330), is rotatable (R) about theaxis of rotation (A) from an open position (300, 900) where the radially inwards extending portions (1220) are aligned with the open slots (340), to a locked position (500, 910) where the periphery (1210) of the locking member (360) at least partly covers the open slots (340).

4. The tool driver (210) according to any previous claim, where the locking member (360) is a spring ring or circlip with an annular periphery (1210) broken by the radially inwards extending portions (1220).

5. The tool driver (210) according to any previous claim, where the locking member (360), when received in the annular groove (330), is biased in an outwards radial direction (Do) and compressible in an inwards radial direction (Di).

6. The tool driver (210) according to any previous claim, where the locking member (360) comprises legs (1230) operable by hand to compress the locking member (360) in the inwards radial direction (Di).

7. The tool driver (210) according to claim 6, where handle portions (1232, 1234) of increased axial extension are formed on the legs (1230) of the locking member (360).

8. The tool driver (210) according to any previous claim, where at least one abutment (1010, 1020) is formed on the tool driver (210), where the abutment (1010, 1020) is arranged to prevent rotation of the locking member (360) past the locked position and / or past the open position.

9. The tool driver (210) according to claim 8, where the locking member (360) comprises an axial protrusion (1 1 10) arranged to cooperate with at least one abutment (1010, 1020) formed in the central aperture (310) of the tool driver (210) to prevent rotation of the locking member (360) past the locked position and / or past the open position.

10. The tool driver (210) according to claim 8, where the abutment is a discontinuity of the annular groove (330) arranged to cooperate with a matching portion formed on the locking member (360).11 . The tool driver (210) according to any previous claim, where the locking member (360) comprises a radial protrusion (365) that extends out radially from the periphery (1210) of the locking member (360).

12. The tool driver (210) according to any previous claim, comprising one or more spring loaded elements, such as spring plungers, arranged to engage the locking member at respective predetermined positions to releasably hold the locking member (360) in the open position and / or in the locked position.

13. The tool driver (210) according to any of claims 1 -2, where the locking member (360) comprises a central hub portion (1310) with spokes (1320) extending radially outwards to peripheral portions (1330) matched to the annular groove (330), where the peripheral portions (1330) are configured to cover the open slots (340) in a nominal position of the locking member (360), where the peripheral portions (1330) are arranged to move in an inwards radial direction (Di) away from the open slots (340) in response to a pressure applied to the central hub portion (1310) to allow the tool holder (220) to traverse the one or more open slots (340) in the insertion direction (I) past the annular groove (330) and into the received position.

14. The tool driver (210) according to claim 13, where abutments (1410) are arranged on the tool driver (210) in direction radially inwards from the peripheral portions (1330), where the abutments (1410) are arranged to prevent movement by the peripheral portions (1330) in the inwards radial direction (Di) by more than a predetermined distance.

15. The tool driver (210) according to claim 13 or 14, where the annular groove (330) comprises sections of reduced radial depth matched to respective separations (1340) between the peripheral portions (1330) on the locking member (360).

16. The tool driver (210) according to any previous claim, where the locking member (360) is formed from sheet metal (1200-1202) or from metal wire (1203-1205).

17. The tool driver (210) according to any previous claim, comprising the locking member (360).

18. Concrete surface processing equipment (100) comprising a tool driver (210) according to any of claims 1 -17.

19. A locking member (360) arranged to be received in an annular groove (330) formed in a side wall (320) of a central aperture of a tool driver (210), the locking member having a periphery (1210, 1350) extending in a plane (P), where the periphery (1210, 1350) of the locking member (360) is matched to a geometry of the annular groove (330), where the locking member (360) comprises legs (1230) operable by hand to compress the locking member (360) in an inwards radial direction (Di) of the locking member (360).

20. The locking member (360) according to claim 19, where the locking member (360) is a spring ring or circlip with an annular periphery (1210) broken by radially inwards extending portions (1220).

21. The locking member (360) according to claim 19 or 20, where the legs (1230) are covered by a resilient and / or friction promoting material (380).

22. The locking member (360) according to claim 19, where the locking member (360) comprises a central hub portion (1310) with spokes (1320) extending radially outwards to peripheral portions (1330) matched to the annular groove (330).

23. A tool holder (220) arranged to be received along an axis of rotation (A) and held in position by a tool driver (210), the tool holder (220) being arranged to hold one or more abrasive tools (230) for processing a concrete surface, the tool holder (220) having a central aperture with at least two radially inwards extending tongues (350) arranged a distance below a tool plane of the tool holder (220), where the tool holder comprises a locking member (360) according to any of claims 19-22.

24. Concrete surface processing equipment (100) comprising a tool holder (220) according to claim 23.

25. A locking arrangement (210, 220, 360) for a concrete surface processing equipment (100), the arrangement comprising the tool driver (210) according to any one of the claims 1 -17, the tool holder (220) according to claim 23, and the locking member (360) according to anyone of the claims 19-22, wherein in the locked position the tool driver (210) and the tool holder (220) are axially fixed in relation to each other by means of the locking member (360) and together rotatable about the axis of rotation of the tool driver (210).

26. Concrete surface processing equipment (100) comprising the locking arrangement (210, 220, 360) according to claim 25, wherein the concrete surfacing equipment (100) is preferably a floor grinder (100).

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