GB2423271A

GB2423271A - Mechanism for locking a scraping tool

Info

Publication number: GB2423271A
Application number: GB0602459A
Authority: GB
Inventors: Guanghong Luo; Qingsheng Yang; Songnian Chen
Original assignee: CHANGZHOU SAIDI ELECTRIC Manufacturing C
Current assignee: CHANGZHOU SAIDI ELECTRIC Manufacturing C
Priority date: 2005-02-18
Filing date: 2006-02-07
Publication date: 2006-08-23
Also published as: DE102006006592A1; FR2882284A1; CN2808465Y; GB0602459D0; FR2882284B1

Abstract

The tool 1 of an operating appliance having a housing 12 is connected to a drive device so as to be driven in an oscillating manner in the direction of its longitudinal axis 18. A tool holder 6 and a rear tool holder 5 guide the tool longitudinally. A bore (A) in the rear tool holder 5 extends at a right angle to the longitudinal axis 18. A pin 2 is guided at one end in the bore (A) so as to be movable in the direction of the axis 51 of the bore, and a compression spring 3 is arranged to press the pin 2 out of the bore. A slide 4 displaceably mounted in a housing wall 12a has a slide wedge 65 with a sliding edge 66 which rests slidably on the other end of the pin 2 as an abutment. As a result of reciprocating movement of the slide 4, on account of the action of the slide wedge 65 and on account of the force of the spring 3, the pin 2 is movable in the axial direction of the bore (A) and is capable of being moved into and out of a hole 75 in the tool 1 so as to lock it and unlock it respectively. The tool may be an electric scraper.

Description

Mechanism for Locking a Scraping Tool The present invention relates to a

mechanism or device for locking a longitudinally oscillating tool, such as a scraping tool, which is used to lock the corresponding tool in an appliance (scraper) when it is inserted and to release it when it is removed.

An electric scraper is an appliance with a reciprocating operating head or scraping tool. It is used for carving wood or removing paint or adhesive, in particular in con- junction with the renovation of dwellings and houses. In this case it is necessary for the operators of the scraper to change the scraping tool frequently on account of different materials. It is necessary in each case to prevent the scraping tool of the electric scraper from getting lost (on grounds of safety). The majority of scrapers commercially available at present generally use a screw, a spring clamp or SDS locking for locking or fixing the scraping tools. Some of these solutions are extremely complicated, whereas others are not practicable for changing scraping tools.

It would therefore be desirable to be able to overcome the drawbacks mentioned above and to provide a locking device which allows scraping tools to be changed in a trouble-free, simple and rapid manner.

The present invention provides a locking device as set forth in claim 1.

In particular, the invention provides locking device for a tool of an operating appliance having a housing, in particular for a scraping tool of an electric scraper, wherein the tool is connected to a drive device of the operating appliance so as to be capable of being driven in an oscillating manner in the direction of its longitudinal axis and wherein the locking device has, arranged in the housing in each case: a front tool holder and a rear tool holder with apertures for the insertion of the tool, in which the tool is guided so as to be movable in the direction of its longitudinal axis, wherein a bore is provided in the rear tool holder, the axis of which bore extends at a right angle to the longitudinal axis of the tool;a pin which is guided at one end thereof in the bore so as to be movable in the direction of the axis of the bore; a compression spring which is arranged so as to press the pin out of the bore; and a slide mounted so as to be displaceable in a housing wall, with a slide wedge with a sliding edge which rests in a maimer capable of sliding on the other end of the pin as an abutment, wherein the pin as a result of reciprocating movement of the slide on account of the action of the slide wedge and on account of the force of the spring is movable in the direction of the axis of the bore and is capable of being moved into and out of a hole in the tool so as to lock it and unlock it respectively.

Advantageous further developments of the invention are set out in the subclaims.

The invention is explained in greater detail below with reference to the accompanying drawings by way of example. In the drawings: Fig. 1 is a side view of the front part of a head end of a scraper with a locking device according to the invention in a position in which the scraping tool can be removed, in which case a half-shell of a housing of the scraper is removed; Fig. 2 shows the scraper of Fig. 1 with the scraping tool locked; Fig. 3 is a view of the entire head end of the scraper in the position of Fig. 1; Fig. 4 is a view of the entire head end of the scraper as shown in Fig. 3 in the position of Fig. 2; of Fig. 2; Fig. 5 is a section along the line A-A in Fig. 4; Fig. 6 is a plan view of a scraping tool suitable for the locking device according to the invention; Fig. 7 is a rear view of a front sliding and rolling bearing of the locking device accor- ding to the invention; Fig. 8 is a section through the front sliding and rolling bearing as shown in Fig. 7 along the line B-B; Fig. 9 is a front view of a rear sliding and rolling bearing of the locking device accor- ding to the invention, and Fig. 10 is a section through the rear sliding and rolling bearing as shown in Fig. 9 along the line C-C.

An electric scraper usually comprises a rear handle part (not shown) for gripping and guiding the scraper by an operator and a front head end 10 (Figs. 3, 4) which adjoins the handle part and in which inter alia a scraping tool 1 is mounted and projects in part out of it. In addition, a scraper of this type has a housing 12 which is advan- tageously formed in two parts along a longitudinal central plane 11 (Fig. 5) of the scraper and which comprises two half shells 82 and has a housing wall 12a, the two half shells 82 being connected to each other in a manner known per se by way of plug-in and/or screw connexions (not shown). A drive device and the locking device according to the invention for the scraping tool 1 are additionally received in the housing 12 which advantageously consists of plastics material.

The locking device shown in Figs. I to 4 has a front tool holder 6, a rear tool holder 5, a pin 2, a spring 3 and a slide 4.

The front tool holder 6 and the rear tool holder 5 are arranged one behind the other in a line which is parallel to a motor shaft (not shown) which is advantageously associated with the drive device. The scraping tool 1 is connected to the drive device so as to be capable of being driven in an oscillating manner in the direction of its longitudi- nal axis 18. To this end the motor shaft is connected for example in a maimer known per se to an electric motor (not shown) and a bevel-gear mechanism 16. In order that the scraping tool 1 can perform the oscillating movement, it is mounted in the two tool holders 5, 6 50 as to be displaceable in the direction of its longitudinal axis 18 and otherwise non-displaceable and rotationally fixed.

The two tool holders 5 and 6 preferably consist of metal, more preferably of steel, and comprise apertures extending in the direction of the longitudinal axis 18 of the tool for the introduction of the scraping tool 1, in particular for the introduction of a plate- shaped and cuboid-shaped shaft 20 of the scraping tool 1. In this case the two tool holders 5, 6 are for example axial bearings, for example in the form of sliding bearings or rolling bearings. In accordance with a preferred embodiment, the tool holders 5, 6 are constructed in the form of combined sliding and rolling bearings 21, 22 (Figs. 1 to 4, 7 to 10). In this case the two sliding and rolling bearings 21, 22 are surrounded locally by the housing 12 of the scraper, and are mounted so as to be non-displaceable in the latter (Figs. 3, 4).

The front sliding and rolling bearing 22 (Figs. 1 to 4, 7, 8) is advantageously designed in the form of a hollow cuboid open towards the front with lateral walls 23 parallel to each other and - in the fitted state - to the longitudinal central plane 11 of the housing 12, a cover wall 24, a base wall 25 parallel thereto and a rear wall 26. In addition, the front sliding and rolling bearing 22 is preferably made symmetrical with respect to a longitudinal plane of symmetry 13, which is parallel to the lateral walls 23.

A front guide slot 27, which is preferably cuboid-shaped and extends through the rear wall 26 and which extends at a right angle to the longitudinal plane of symmetry 13 of the front sliding and rolling bearing 22, is formed in the rear wall 26 of the front sliding and rolling bearing 22. The shaft 20 of the scraping tool 1 is passed through the guide slot 27 in the fitted state of the scraping tool 1. To this end the guide slot 27 is advan- tageously dimensioned in such a way that the distance from an upper edge 28 of the slot to a lower edge 29 of the slot parallel thereto is slightly greater than the height of the tool shaft 20, i.e. the distance of a top side 20a of the tool shaft from an underside 20b of the tool shaft, and that the distance of mutually parallel lateral edges 30 of the slot corresponds to the width of the tool shaft 20, i.e. the distance of two mutually opposed lateral faces 20c of the tool shaft, so that the scraping tool 1 is guided in the guide slot 27 so as to be capable of sliding in the direction of its longitudinal axis 18 whilst being restricted with positive locking laterally.

In addition, the front sliding and rolling bearing 22 has a roller body, for example in the form of a cylinder 31, which is orientated with its axis 32 at a right angle to the longitudinal plane of symmetry 13 of the front sliding and rolling bearing 22. In order to mount the cylinder 31, the front sliding and rolling bearing 22 comprises two cylinder-mounting webs 33 which project into the interior of the sliding and rolling bearing 22 in the shape of a hollow cuboid and extend parallel to the base wall 25 and to the longitudinal plane of symmetry 13 and which are formed integrally on two lateral inner walls 36 in each case. The said cylinder-mounting webs 33 have in each case an upper edge 34 which is parallel to the cover wall 24 and the distance of which from an inner wall 35 of the cover substantially corresponds to the diameter of the cylinder 31.

In this case the distance between the two laterally opposed cylindermounting webs 33 likewise advantageously corresponds to the width of the tool shaft 20. The length of the cylinder 31 substantially corresponds to the distance between the two opposed lateral inner walls 36 of the front sliding and rolling bearing 22, so that the cylinder 31 is guided between the upper edge 34 of the web and the inner wall 35 of the cover and between the two opposed lateral inner walls 36 and can roll on the upper edge 34 of the web and the inner wall 35 of the cover about its axis 32. In the direction of the longi- tudinal axis 18 of the tool the freedom of movement of the cylinder 31 is limited by the rear wall 26 and, towards the front, by the housing 12 which surrounds the front sliding and rolling bearing 22.

The rear sliding and rolling bearing 21 (Figs. 1 to 4, 9, 10) with its longitudinal plane of symmetry 14 is designed in the form of a hollow cuboid open towards the rear with lateral walls 37 likewise parallel to each other and to the longitudinal plane of symmetry 14, a cover wall 38, a base wall 39 parallel thereto and with a front wall 40 instead of the rear wall 26 of the front sliding and rolling bearing 22, the front wall 40 being constructed with a substantially greater wall thickness than the other walls 37, 38, 39 of the rear sliding and rolling bearing 21. The front wall 40 has formed in it a rear guide slot 41 for guiding the tool shaft 20, which extends at a right angle to the longi- tudinal plane of symmetry 14 and to the lateral walls 37 of the rear sliding and rolling bearing 21 and is likewise advantageously dimensioned in such a way that the distance from an upper edge 42 of the slot to a lower edge 43 of the slot parallel thereto is slightly greater than the height of the tool shaft 20, and that the distance between mutually parallel lateral edges 44 of the slot corresponds to the width of the tool shaft 20, so that in the fitted state the scraping tool 1 is guided in the guide slot 27 so as to be likewise capable of sliding in the direction of the longitudinal axis 18 of the tool whilst being restricted with positive locking laterally. In order to facilitate the introduction of the tool shaft 20, the front continuous edges 15 of the rear guide slot 41 are advan- tageously bevelled (Figs. 1 to 4).

In addition, the rear sliding and rolling bearing 21 has a rolling body, preferably in the form of a cylinder 45, the axis 46 of which is at a right angle to the longitudinal plane of symmetry 14. Two cylindermounting webs 47, which project into the interior of the rear sliding and rolling bearing 21 in the form of a hollow cuboid and which extend parallel to the longitudinal plane of symmetry 14 and are formed integrally on two lateral inner walls 50 in each case, are provided in turn in order to mount the cylinder 45. The cylinder-mounting webs 47 of the rear sliding and rolling bearing 21 have in each case a lower edge 48 which is parallel to an inner wall 49 of the base and the distance of which from the inner wall 49 of the base corresponds substantially to the diameter of the cylinder 45. In this case the distance between the two opposed cylinder- mounting webs 47 advantageously corresponds in turn to the width of the tool shaft 20.

The length of the cylinder 45 preferably corresponds substantially to the distance between the two opposed lateral inner walls 50, so that the cylinder 45 is guided between the lower edge 48 of the web and the inner wall 49 of the base and between the two opposed lateral inner walls 50 and can roll on the lower edge 48 of the web and the inner wall 49 of the base about its axis 46. In the direction of the longitudinal axis 18 of the tool the freedom of movement of the cylinder 45 is limited by a front inner wall 40a of the front wall 40 and, towards the rear, by the housing 12 which surrounds the rear sliding and rolling bearing 21 (Figs. 3, 4).

In the fitted state of the two sliding and rolling bearings 21, 22 in which the bearings 21, 22 are arranged with their longitudinal planes of symmetry 13, 14 parallel to the longitudinal central plane 11 of the housing 12, the distance between the two cylinders 31, 45 of the front and the rear sliding and rolling bearings 21, 22 from each other in a direction parallel to the longitudinal central plane 11 and at a right angle to the longitudinal axis 18 of the tool is equal to the height of the shaft 20 of the scraping tool 1, so that the said tool shaft 20 is clamped between the two cylinders 31, 45 and is guided so as to be movable in the direction of the longitudinal axis 18 of the tool, the cylinders 31, 45 roIling on the top side 20a of the tool and the underside 20b of the tool respectively.

In addition, according to the invention a bore A, in particular a throughbore, is pro- vided in the rear tool holder 5 in an orientation at a right angle to the scraping tool 1 introduced into the tool holder 5, in particular to the longitudinal axis 18 of the tool.

The said through-bore A is preferably formed in the enlarged front wall 40 of the rear sliding and rolling bearing 21 and has an axis 51 which is orientated parallel to the longitudinal plane of symmetry 14 and thus to the longitudinal central plane 11 and at a right angle to the longitudinal axis 18 of the tool (Figs. ito 4, 9, 10).

One end of the securing pin or locking pin 2 is introduced into the said bore A and is advantageously guided in the latter so as to be movable in the direction of the axis 51 of the bore, whilst the other end of the pin 2 is acted upon by the slide 4, and this will be discussed in greater detail below. To this end the pin 2 has an advantageously cylindrical shaft 52, the diameter of which corresponds substantially to the diameter of the bore A and which is guided so as to slide locally in the bore A with positive locking.

In addition, the pin 2 has a head 53 which adjoins the shaft 52 and is enlarged with respect to the latter and which has an underside 54, preferably flat, and a top side 55, preferably convex (Figs. 1, 2).

The compression spring 3 (Figs. 1 to 4) is arranged around the shaft 52 of the pin 2 and is supported at one end on an outer cover wall 56, advantageously flat, of the rear sliding and rolling bearing 21 and at the other end on the underside 54 of the pin, so that the compression spring 3 is arranged so as to press the pin 2 out of the bore A in the direction of the axis 51 of the bore. In order to improve the guidance of the pin 2 and to prevent jamming, the head 53 of the pin is preferably additionally guided with its lateral wall 53a in a cylindrical opening 57 in the housing 12 so as to be movable in the axis 51 of the bore (Figs. 3, 4).

The pin 2 can move up and down in the bore A with the aid of the spring 3, when the slide 4 is moved or forced forwards or backwards.

The slide 4 (Figs. 1 to 5) of the locking device according to the invention has an ad- vantageously cuboid-shaped slide plate 58 with a flat top side 59, an underside 60 parallel thereto, two mutually opposed lateral edges 61, a front edge 62 and a rear edge 63 opposite the latter. In addition, the slide 4 has an operating knob 64 which is formed integrally on the slide plate 58 and projects from the top side 59 of the plate and is shaped in an ergonomic maimer and which is used for moving the slide 4 in the housing 12 by the operator, which will be explained in greater detail below. The operating knob 64 is preferably arranged centrally with respect to the extension of the lateral edges 61 of the plate and the front and rear edges 62, 63 of the plate and is made hollow and open with its wall (not shown) towards the underside 60 of the plate.

In order to ensure that the slide 4 can move along the housing 12 of the scraper and is capable of being positioned in the housing 12 of the slide 4, a positioning attachment or a catch projection 8 is provided on each side of the slide 4. The said catch projections 8 are formed integrally on the two lateral plate edges 61 of the slide 4, pre- ferably centrally with respect to the extension of the two lateral plate edges 61, and extend away from the respective lateral plate edge 61, and they have a triangular profile tapering to a point and with a front and a rear flank 80, 81 in each case (Fig. 5).

In accordance with a further embodiment (not shown), the flanks of the catch pro- jections are rounded off in the form of a single continuous flank, for example are made semicircular in shape.

In addition, a slot 9 is provided on each side of the slide 4. The slots 9 advan- tageously extend parallel to the lateral edges 61 of the plate on each side of the operating knob 64 and form springing webs 17 situated on the outside on each side of the slide plate 58, on which springing webs 17 the catch projections 8 are integrally formed (Fig. 5).

The cross-section of the slide 4 is generally triangular. In particular, the slide 4 has a slide wedge 65 (Figs. 1 to 4) which is preferably plateshaped and is triangular in a side view and which extends away from the underside 60 of the plate and at a right angle thereto and parallel to the lateral edges 61 of the plate. In addition, the slide wedge 65 is preferably arranged centrally with respect to the extension of the lateral edges 61 of the plate and the front and rear edges 62, 63 of the plate. The slide wedge has a front or sliding edge 66, which advantageously forms an acute angle u with the underside 60 of the plate, and a rear edge 67, which preferably forms a right angle fE with the underside 60 of the plate.

In the fitted state the slide 4 is mounted with its slide plate 58 in a cuboid-shaped recess 68 in the housing wall 12a. This recess 68 has a level, flat top side 69, an underside 70 parallel to thereto, two mutually parallel and mutually opposed lateral edges 71, a front edge 72 and a rear edge 73 opposite thereto and parallel thereto. In addition, a through-opening 74 is provided in the housing 12 in the region of the top side 69 of the recess, through which the operating knob 64 projects out of the housing 12 and can be actuated by the operator. In this case the distance of the top side 69 of the recess from the underside 70 of the recess corresponds to the distance of the top side 59 of the plate from the underside 60 of the plate, the distance of the lateral edges 71 of the recess from each other corresponds substantially to the distance of the lateral edges 61 of the plate from each other, and the distance of the front edge 72 of the recess from the rear edge 73 of the recess is greater than the distance of the front edge 62 of the plate from the rear edge 63 of the plate, so that the slide 4 is guided in the recess 68 in the housing wall 12a so as to be movable by a limited amount in the direction of the lateral edges 61 of the plate. In this case the freedom of movement of the slide 4 in the housing 12 is preferably limited by a front and a rear stop edge 74a, 74b (Figs. 1, 2) of the through-opening 74, against which the operating knob 64 strikes during the locking and unlocking, which will be discussed in greater detail below.

In the assembled state the recess 68 and, as a result, the slide 4 are positioned in the housing 12 in such a way that the flat sliding edge 66 of the wedge is orientated parallel to the longitudinal axis 18 of the tool and at a right angle to the axis 51 of the bore A and rests on the top side 55 of the pin so as to be capable of sliding against the pressure of the spring 3. As a result of this, the sliding edge 66 of the wedge limits the freedom of movement of the pin 2 out of the bore A in the direction of the axis 51 of the bore and thus acts as an abutment.

In addition, in total two positioning openings or catch openings 7 are provided in the housing 12 on each side of the housing 12 of the scraper, and they co-operate with the catch projections 8 of the slide 4 of the scraper (Fig. 5). The catch openings 7 are advantageously formed one behind the other in the lateral edges 71 of the recess as viewed in the direction of the lateral edges 71 of the recess. In this case two of the catch openings 7 are arranged opposite each other in the housing 12 in each case and, as a result, form a pair of rear catch openings 7a and a pair of front catch openings 7b respectively.

The slot 9 or the housing 12 in the region of the slot 9, in particular the springing webs 17, are deformable, advantageously compressible in a resilient or springing manner andlor back-deformable, so that the respective catch projection 8 can enter the respective catch opening 7 in the housing 12 of the scraper and can move out of it when the slide 4 is moved under the action of force by the operator, which will be explained in greater detail below.

In order to ensure that the scraping tool 1 is capable of being locked in a reliable maimer by the pin 2, a hole or a bore 75 is provided, which has a similar shape to the cross-section of the pin 2, namely in the tool 1, advantageously at the rear end of the tool shaft 20 (see Fig. 6). The bore 75 is preferably designed in the form of an oval hole or an elongate hole 75, which has a longitudinal extension in the direction of the longitudinal axis 18 of the tool and which extends from the top side 20a of the tool shaft to the underside 20b of the tool shaft. The diameter of the elongate hole 75 corresponds to the diameter of the shaft 52 of the pin 2. The freedom of movement of the scraping tool 1 is determined by the length of the elongate hole 75.

The maimer of operation of the locking device will now be explained below: When the device is in the position shown in Figs. 1 and 3, the slide 4 is in a higher or rear position and the catch projection 8 of the slide 4 is positioned by the catch openings 7a positioned at a higher level or to the rear in the housing 12, i.e. the catch projections 8 of the slide 4 engage in the rear catch openings 7a. In this case the operating knob 64 rests against the rear stop edge 74b of the through- opening 74. In this position the pin 2 is likewise in a higher position - pressed slightly further out of the bore A - under the action of force of the spring 3, 50 that the pin 2 does not engage in the elongate hole 75. In this position the tool 1 can be inserted into the correct posi- tion. The scraping tool 1 can be moved into this position or out of this position, it is not locked.

As a result of the slide 4 being displaced in the direction of the front stop edge 74a against the force of the spring 3 which acts upon the sliding edge 66 of the wedge by way of the top side 55 of the pin, the slide 4 or the entire locking mechanism is moved into the locked position shown in Figs. 2, 4 and 5. In this case the catch projections 8 are first pushed out of the rear catch openings 7a against the resistance of the resilient springing webs 17, as the slide plate 58 is compressed in the region of the slots 9. In this case the front flanks 80 of the catch projections act like a wedge, so that the slide plate 58 is gradually compressed. In the compressed state the slide 4 is moved forwards and downwards until it is in a lower or forward position and its catch projections 8 come to rest in the catch openings 7b positioned lower down or at the rear in the housing 12, i.e. until the catch projections 8 engage in the rear catch openings 7b and until the operating kxiob 64 strikes against the front stop edge 74a. In this case the slide plate 58 is automatically pressed apart again in the region of the slots 9 on account of its resilient back-deformability, i.e. the springing webs 17 spring back. The pin 2 is then likewise present in a lower position inserted further into the bore A under the action of force by the slide 4, in particular by the wedge 65 of the slide 4 which has likewise been pushed towards the rear parallel to the longitudinal axis 18 of the tool and downwards parallel to the axis 51 of the bore. In this situation the tool 1 is locked (see Fig. 5 likewise), since the pin 2 engages in the bore 75 or the elongate hole in the scraping tool 1. The scraping tool 1 is thus mounted so as to be movable by the pin 2 by only a limited amount in the direction of the longitudinal axis 18 of the tool, namely by the amount by which it oscillates during operation.

In order to unlock the scraping tool 1, the slide 4 is pushed back again in the opposite direction into its upper or rear position by the operator. In this case the resistance of the slide plate 58 must again first be overcome in order to press the catch projections 8 out of the front catch openings 7b, as the slide plate 58 is compressed in the region of the slots 9, this time as a result of the wedge action of the rear catchprojection flanks 81. The movement of the slide 4 above and to the rear is assisted by the force of the spring 3. In addition, the pin 2 is moved upwards or further out of the bore A by the force of the spring 3 when the slide 4 is moved towards the rear and the sliding edge 66 of the wedge is pushed towards the rear parallel to the longitudinal axis 18 of the tool and upwards parallel to the axis 51 of the bore.

In a preferred embodiment of the invention (not shown) the locking mechanism comprises only one pair of front catch openings 7b into which the catch projections 8 engage in the locked position. In the unlocked position the slide 4 is then held merely by the force of the spring 3 which presses the pin 2 and thus the slide 4 upwards or towards the rear, in which case the operating knob 64 is pressed against the rear stop edge 74b.

It is also, of course, within the scope of the invention for the slide wedge to be mounted so as to be displaceable parallel to the direction of the longitudinal axis of the tool and for the sliding edge of the wedge to be arranged at an angle to the longitudinal axis of the tool. In this case too the pin is moved by the action of the wedge.

The arrangement according to the invention has the advantage of a simple design, the ability of being easy to produce, and the facility of being convenient for the

introduction and removal of different tools 1.

Claims

CLAIMS: 1. A locking device for a tool of an operating appliance, the tool

having a longitudinal axis along which the tool is drivable in an oscillating maimer, the locking device comprising: a) tool holders with respective apertures for guiding the tool so as to be movable in the direction of its longitudinal axis, one of the tool holders having a bore, the axis of which extends transversely to the longitudinal axis of the tool when mounted in the tool holders; b) a pin, one end of which is guided in the said bore;

c) a spring arranged to urge the pin out of the said bore, and d) a slide mounted so as to be displaceable in a housing wall and having a slide wedge with a sliding edge which rests on the other end of the pin, reciprocating movement of the slide, on account of the action of the slide wedge and on account of the force of the spring, being capable of causing movement of the pin into and out of a hole in the tool, when mounted in the tool holders, so as to lock it and unlock it respectively.
2. A locking device according to claim 1, in which the tool has a shaft with a flat top side and an underside parallel thereto and preferably two mutually opposed and preferably flat lateral faces.
3. A locking device according to claim 1 or 2, in which the tool is mounted in the tool holders so as to be displaceable only in the direction of its longitudinal axis, otherwise being non-displaceable and rotationally fixed.
4. A locking device according to any preceding claim in which the front tool holder is a sliding and rolling bearing, which is preferably a hollow cuboid open towards the front and with lateral walls parallel to each other, a cover wall, a base wall parallel thereto and a rear wall.
5. A locking device according to claim 4, in which the sliding and rolling bearing is substantially symmetrical with respect to a longitudinal plane of symmetry which is parallel to the lateral walls.
6. A locking device according to claim 5, in which the sliding and rolling bearing has a, preferably cuboid-shaped, front guide slot which extends through the rear wall and which extends at a right angle to the said longitudinal plane of symmetry.
7. A locking device according to claim 6, in which the distance from an upper edge to a lower edge - parallel thereto - of the guide slot is greater than the height of the tool shaft, the distance between mutually parallel lateral edges of the slot preferably corresponding to the width of the tool shaft.
8. A locking device according to any of claims 5 to 7, in which the sliding and rolling bearing has a rolling body, for example in the form of a cylinder, which is orientated with its axis at a right angle to the longitudinal plane of symmetry, wherein two cylinder-mounting webs formed integrally on a lateral inner wall in each case and extending parallel to the base wall and to the longitudinal plane of symmetry and in each case with one upper edge, which is parallel to the cover wall and the distance of which from an inner wall of the cover corresponds to the dia- meter of the cylinder, are preferably provided in order to mount the cylinder, wherein the distance of the two cylinder-mounting webs laterally opposed each other preferably corresponds to the width of the tool shaft and the length of the cylinder preferably corresponds to the distance between the two opposed lateral inner walls.
9. A locking device according to claim 8, in which the cylinder is guided between the upper edge of the web and the inner wall of the cover and between the two opposed lateral inner walls and is mounted on the upper edge of the web and the inner wall of the cover so as to be capable of rolling about its axis.
10. A locking device according to any preceding claim, in which the rear tool holder is a rear sliding and rolling bearing which is preferably a hollow cuboid open towards the reas and with two lateral walls parallel to each other, a cover wall, a base wall parallel thereto and a front wall, wherein the front wall preferably has a thickness substantially greater than the other walls.
11. A locking device according to claim 10, in which the rear sliding and rolling bearing is substantially symmetrical with respect to a longitudinal plane of symmetry which is parallel to the lateral walls.
12. A locking device according to claim 11, in which the rear sliding and rolling bearing has a rear guide slot passing through the front wall in order to guide the tool shaft, which extends at a right angle to the longitudinal plane of symmetry, wherein the distance from an upper edge of the slot to a lower edge of the slot parallel thereto is preferably slightly greater than the height of the tool shaft, and the distance of mutually parallel lateral edges of the slot preferably corresponds to the width of the tool shaft.
13. A locking device according to claim 11 or 12, in which the rear sliding and rolling bearing has a rolling body, for example in the form of a cylinder, the axis of which is advantageously at a right angle to the longitudinal plane of symmetry.
14. A locking device according to claim 13, in which, in order to mount the cylinder, the rear sliding and rolling bearing has two cylindermounting webs which are formed integrally on a lateral inner wall of the rear sliding and rolling bearing in each case and which extend parallel to the longitudinal plane of symmetry and pre- ferably have in each case one lower edge which is parallel to the inner wall of the base and the distance of which from the inner wall of the base preferably corre- sponds to the diameter of the cylinder, wherein the distance between the two cylinder-mounting webs laterally opposed to each other preferably corresponds to the width of the tool shaft and the length of the cylinder preferably corresponds to the distance between the two lateral inner walls.
15. A locking device according to claim 14, in which the cylinder is guided between the lower edge of the web and the inner wall of the base and between the two opposed lateral inner walls and it is mounted on the lower edge of the web and the inner wall of the base so as to be capable of rolling about its axis.
16. A locking device according to any of claims 13 to 15, in which the two sliding and rolling bearings are arranged with their longitudinal planes of symmetry parallel, and preferably co-planar, with a longitudinal central plane of the housing, wherein the distance between the two cylinders of the front and the rear sliding and rolling bearings from each other in a direction parallel to the longitudinal central plane and at a right angle to the longitudinal axis of the tool preferably corresponds to the height of the shaft of the tool.
17. A locking device according to claim 16, in which the shaft of the tool is guided in the front and the rear guide slots so as to be movable in the direction of the longi- tudinal axis of the tool to a limited extent laterally with positive locking, wherein the cylinder of the front sliding and rolling bearing rests against the top side of the tool shaft and the cylinder of the rear sliding and rolling bearing rests against the underside of the tool shaft in a rolling manner in each case.
18. A locking device according to any of claims 11 to 17, in which the said bore is a continuous bore formed in the front wall of the rear sliding and rolling bearing, the axis of the bore being orientated parallel to the longitudinal plane of symmetry.
19. A locking device according to any preceding claims, in which the pin has a cylindrical shaft, the diameter of which corresponds to the diameter of the bore and which is guided locally in the bore so as to capable of sliding in the direction of the axis of the bore with positive locking.
20. A locking device according to claim 19, in which the pin has a head which adjoins the shaft and is enlarged with respect thereto and which has a preferably flat underside and a preferably convex top side.
21. A locking device according to claim 20, in which the spring is a compression spring is arranged around the shaft of the pin and is supported at one end on a preferably flat outer cover wall of the rear sliding and rolling bearing and at the other end on the underside of the head of the pin.
22. A locking device according to claim 20 or 21, in which the head of the pin is guided with a cylindrical lateral wall in a cylindrical opening in the housing so as to capable of sliding in the direction of the axis of the bore.
23. A locking device according to any preceding claim, in which the slide comprises a, preferably cuboid-shaped, slide plate with a flat top side, an underside parallel thereto, two mutually opposed lateral edges, a front edge and a rear edge opposite the latter.
24. A locking device according to claim 23, in which the slide has an operating knob which is formed integrally on the slide plate and projects from the top side of the plate and is preferably shaped in an ergonomic manner and which is preferably arranged centrally with respect to the extension of the lateral edges of the plate and the front and reas edges of the plate and is preferably made hollow and open towards the underside of the plate.
25. A locking device according to any preceding claim, in which a catch projection and a slot are provided on each side of the slide.
26. A locking device according to claim 25, in which the catch projections are integrally formed, preferably centrally with respect to the extension of the two lateral plate-edges, on the two lateral plate- edges of the slide and extend away from the respective lateral plate-edge.
27. A locking device according to claim 25 or 26, in which the catch projections on the slide are triangular and have a front and a rear catchprojection flank.
28. A locking device according to any of claims 23 to 27, in which the slots extend parallel to the lateral edges of the plate on each side of the operating knob and fix springing webs on which the catch projections are integrally formed.
29. A locking device according to any preceding claim, in which the slide wedge is plate-shaped and extends at a right angle to the underside of the plate, away from the latter and parallel to the lateral edges of the plate.
30. A locking device according to claim 29, in which the front or sliding edge of the wedge fonns an acute angle with the underside of the plate, and a rear edge of the wedge preferably forms a right angle with the underside of the plate.
31. A locking device according to any of claims 23 to 30, in which the slide plate is mounted in a cuboid-shaped recess in a housing, which recess preferably has a level, flat top side, an underside parallel thereto, two mutually parallel and mutually opposed lateral edges, a front edge and a rear edge opposite thereto and parallel thereto.
32. A locking device according to claim 31, in which a through-opening, through which the operating knob projects out of the housing and is capable of being actuated, is provided in the housing in the vicinity of the top side of the recess.
33. A locking device according to claim 31 or 32, in which the distance of the top side of the recess from the underside of the recess corresponds to the distance of the top side of the plate from the underside of the plate, and the distance of the lateral edges of the recess from each other preferably corresponds substantially to the distance of the lateral edges of the plate from each other, and the distance of the front edge of the recess from the rear edge of the recess is greater than the distance of the front edge of the plate from the rear edge of the plate.
34. A locking device according to any of claims 31 to 33, in which the slide is guided in the recess in the housing so as to be movable in the direction of the lateral edges of the plate by a limited amount, wherein the freedom of movement of the slide is preferably limited by a front and a rear stop edge respectively of the through- opening, which act as stops for the operating knob.
35. A locking device according to any of claims 31 to 34, in which the recess in the housing and the slide are positioned and dimensioned in such a way that the level sliding edge of the wedge is orientated parallel to the longitudinal axis of the tool and at a right angle to the axis of the bore and is movable in the direction of the axis of the bore and in the direction of the longitudinal axis of the tool.
36. A locking device according to any of claims 25 to 34, in which one or two catch openings, designed so as to co-operate with the catch projections of the slide, is or are provided on each side of the slide.
37. A locking device according to claim 36, in which the catch openings are formed in succession - as viewed in the direction of the lateral edges of the recess - in the lateral edges of the recess, wherein two of the catch openings are preferably arranged opposite each other in each case, so that a pair of rear catch openings and a pair of front catch openings respectively are present.
38. A locking device according to claim 36 or 37, in which the slide plate is capable of being compressed in a resiliently back-deformable manner in the region of the slots, andlor the springing webs are back- deformable in a resilient or springing manner.
39. A locking device according to claim 36 or 37, in which the housing is resiliently back-deformable in the region of the catch openings.
40. A locking device according to any preceding claim, in which the hole is an elongate hole which has a longitudinal extension in the direction of the longitudinal axis of the tool, the diameter of the elongate hole preferably corresponding to the diameter of the shaft of the pin.
41. A locking device according to any preceding claim, in which the hole is continuous from the top side of the tool to the underside of the tool.
42. A locking device according to any preceding claim, in which, in the unlocked posi- tion of the locking device the slide is in a higher or rear position in which catch projections preferably engage in rear catch openings.
43. A locking device according to claim 42, in which the operating knob rests against the rear stop edge of the through-opening.
44. A locking device according to claim 42 or 43, in which the slide is held in the rear position on account of the force of the spring.
45. A locking device according to any preceding claim, in which, in the locked position of the locking device the slide is in a front position in which the catch projections engage in front catch openings.
46. A locking device according to claim 45, in which the operating knob rests against the front stop edge.
47. A locking device according to claim 45 or 46, in which the pin engages in or through the hole of the tool.
48. A locking device according to any of claims 45 to 47, in which the tool is mounted so as to be movable by a limited amount in the direction of the longitudinal axis of the tool.
49. A locking device substantially or described with reference to, and as shown in, the accompanying drawings.