GB1574157A

GB1574157A - Implements

Info

Publication number: GB1574157A
Application number: GB16548/77A
Authority: GB
Original assignee: Gardena Kress and Kastner GmbH
Current assignee: Gardena Manufacturing GmbH
Priority date: 1976-04-22
Filing date: 1977-04-21
Publication date: 1980-09-03
Also published as: SE429518B; FR2348794B3; AT357810B; JPS60188208U; FR2348794A1; NL7704312A; NO142936C; IT1076031B; DE2617622C2; DE2617622A1; JPS6227695Y2; AU2433477A; NO771305L; JPS52151457A; ZA772438B; AU507279B2; ATA252677A; SE7704602L; ES458060A1; BE853640A

Description

(54) IMPROVEMENTS IN IMPLEMENTS (71) We, GARDENA KRESS & I(ASTNER GmbH., a German Company of 5, Boschstrasse, 7900 Ulm/Donau, Federal Republic of Germany, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: The invention relates to implements, such as garden tools, and more particularly to means for attaching the implement head to a handle.

Gardening tools normally have a conical sleeve into which is fitted the end of a wooden handle which is secured by means of a screw or a nail which is screwed or hammered into the handle though a hole in the sleeve. It is also known to provide domestic implements, such as brushes and brooms, with a conical screw-threaded sleeve into which a handle having a conical screwthreaded spigot is screwed.

A feature of the invention is to provide an implement head with a coupling part which renders it possible to couple a handle to the implement head in a particularly rapid and simple manner, and which is not susceptible to dirt and which can be readily manufactured in large numbers.

In accordance with the invention, an implement head is provided with a male coupling pin which forms the male part of a coupling by which the implement head can be attached to a coupling sleeve which forms a female coupling part on a handle, in which the coupling pin has an elongate stepped configuration, reducing in lateral dimension towards its free end, to define at its region adjacent the implement head a radial guide portion of larger lateral dimension and at its region adjacent its free end a polygonally sectioned portion of smaller lateral dimension for preventing the coupling pin from turning in the coupling sleeve.

A coupling pin of this type renders it possible, in cooperation with a coupling sleeve which is of very simple construction and which can be operated rapidly, to couple the implement head to the handle in a rapid and simple manner such that one handle can be used for a large number of different (or, alternatively, identical) implement heads.

Thus, the user requires only one handle and can connect thereto all types of different gardening tools which he requires for optimum cultivation of his garden. The susceptability of the overall coupling to damage due to dirt and wear is substantially reduced by virtue of the fact that the coupling pin of particularly simple and robust external construction is provided on the implement head, since the coupling pin does not tend to become soiled and any dirt adhering thereto drops therefrom, or is at least easily visible so that it can be removed. However, there is the greater risk of the implement head being soiled than the handle.

A set of various implement heads and only one handle requires the manufacture of a larger number of implement heads than handles. Therefore, it is also economically advantageous that the pin, which is the simpler part of the coupling to manufacture, is mounted on the implement head.

According to the type of the implement and the stress to which it is subjected, the coupling pin can be made entirely from plastics material or entirely from metal. However, in the case of implement heads made from metal, it is particularly preferable that the main portion of the coupling pin is a metal part, such as a hexagonal bar, onto which is slipped a plastics sleeve which, in.

one or more steps, merges into the radial guide portion which fits in the interior of the coupling. Thus, manufacture can be effected in the simplest manner and the insertion of the pin into the coupling sleeve is simplified. The metal part absorbs the pushing forces, the pulling forces and, if required,.

the torsional forces, while, owing to the fact that the p]astics material is adaptable and less hard, the radial guide surface on the mounted plastics sleeve ensures that any play which might exist does not lead to rattling, and wedging does not lead to seizing.

It is particularly important that the abut ment in the direction of pushing and a locking surface to be engaged by a locking membcr on the coupling sleeve are, advantageously, spaced at only a short axial distance apart and are arranged preferably at the free end of the coupling pin. Thus, tolerances have no material affect on the reliable operation of the coupling, this being particularly important since a system is involved in which a large number of different tools are to be coupled to one another.

The invention is further described, by way of example, with reference to the accompanying drawings in which: Fig. 1 is a perspective view of a gardening set, constructed in accordance with the invention and comprising a handle and three tool heads, any of which can be coupled to the handle, Fig. 2 is a longitudinal section through a coupling by means of which the handle and the gardening tools are connectible to one another, shown during coupling or uncoupling, Fig. 3 is an illustration similar to that shown in Fig. 2, but the handle and a gardening tool head are shown firmly connected to one another by the coupling, and the entire coupling pin of the coupling is made from plastics material, Fig. 4 is a cross section taken on the line IV-IV of Fig. 3, Figs. 5 and 6 are fragmentary longitudinal sections through a different embodiment of a coupling, showing the coupling sleeve and a coupling pin disassembled, Fig. 7 is a fragmentary longitudinal section through the coupling similar to that of Figs. 5 and 6, but shown in the coupled state, and with a coupling pin made from plastics material, and Fig. 8 is a fragmentary longitudinal section through a further embodiment of coupling.

Fig. 1 shows a gardening tool set comprising a handle 11 having a coupling 12 at one end, and a plurality of different tool heads 13, 14, 15 each of which has a coupling nipple or pin 16 or 161 of elongate stepped configuration, reducing in lateral dimension towards its free end. The coupling pins 16 are rigidly and non-releasably attached to the tool heads. The illustrated tool heads comprise a harrow 13, a hoe 14 and a besom 15 which is made entirely from plastics material. All types of gardening tools requiring a handle can be included in the set by providing the tool heads with the corresponding coupling pin. It is also possible to include handles of various constructions and/or various dimensions in a set comprising a large number of gardening tools. Thus, the cost of acquiring, accommodating and transporting the gardening tools can be considerably reduced. Hitherto, each gardening tool had to have an individual handle, thus causing considerable difficulties when storing the tools in a small space. The described gardening tool set renders it possible to use the most suitable working tool at any given time, particularly for small gardens and those not having any special tool-storage space. Nevertheless, the storage space available is adaquate, since only one handle is required in order to use the large number of tool heads which can be stored in a simple manner. A coupling operation can be carried out rapidly and without difficulty.

and the coupling is adequately secure against pressure, tension and turning and is not susceptible to dirt. In particular, the portion of the coupling on the tool head should be of particularly simple construction, since it is manufactured in large numbers and is subjected to soiling to a greater extent than the portion of the coupling located on the handle. Thus, it is advantageous for the male coupling part (the coupling pin) to be located on the tool head and for the female part of the coupling, i.e. the part having a movable locking member, to be located on the handle.

The coupling 12 of Fig. 1 is illustrated in Fig. 2. The entire handle 11 can comprise a tube 17, preferably an aluminium tube, as is shown in Figs. 1 and 2, or, alternatively, as is shown in Fig. 3, it may comprise a wooden handle 18 to which a tubular portion 171 is secured.

An insert 19, made from plastics material, is inserted into the end of the tube 17 facing the tool head and has a flange 21 by which it abuts against the end 20 of the tube.

The insert 19 has a large cylindrical central opening 23 which extends from its mouth 22 at the end of the handle into the interior of the handle to an extent equal to approximately twice to three times its diameter. The insert has a locating portion 24 which is contiguous to the insertion portion formed by the opening 23 and, in the illustrated embodiment, is in the form of an opening having an irregular hexagonal cross section.

As may be seen particularly in Fig. 4, the surfaces of the locating portion slope relatively to one another at 1200 although the individual surfaces are of differing size.

Two broad surfaces 25 are interconnected by a narrower surface 26. Two even narrower connection surfaces 27 are adjacent to the other sides of the surfaces 25 and are interconnected by means of a surface 28.

The surfaces 25 are at an angle of 600 to one another and act as contact surfaces.

The locating portion 24 is offset eccentric ally towards one side of the central longitudinal axis 29 of the insert 19 and of the tube 17, i.e. towards the bottom surface 26 so that a relatively thick-walled portion 30 is formed between the surface 28 and the outer periphery of the insert to receive a screw 33 which forms part of a locking member 31, the screw 33 being screwed into the wall portion 30. The external screw-thread of the screw 33 of the locking member 31 cooperates with an internal screw-thread 32 which is provided in the metal wall of the tube 17 and also in the plastics wall portion 30. The locking member 31 comprises, in addition to the metal screw 33, an actuating handle 34 of plastics material which is injection moulded onto the screw 33. A collar 35 may be provided on the actuating handle 34 to form a limiting stop which, by abutting against the outer surface of the tube 17, prevents the screw 33 from being screwed too far into the tube 17.

The opening forming the locating portion 24 is open towards the inner end 36 of the insert 19, so that any dirt entering the insert can drop therethrough in this direction.

In the case of heavy soiling, it is also pos sible to flush the insert by means of a jet of water. However, a cross member 37 is provided in the region of the inner end 36 and extends transversely across the locating portion 24 (also see the broken lines in Fig.

4) and forms an abutment for limiting the extent to which the coupling pin 16 can be pushed in. The transition between the cylindrical central opening 23 and the hexagonal eccentric locating portion 24 is chamfered to form a guide 38.

In the illustrated embodiment, the coupling pin 16 comprises an hexagonal bar 40 which is connected to the gardening tool head 13 by means of a weld 39 and which has a regular hexagonal cross section, and a plastics sheath 41 which is slipped onto the hexagonal bar with a press fit and which forms a radial guide portion.

The hexagonal bar 40 has, at a relatively short distance from its free end 42, a continuous annular recess which forms a fixed locking surface 43 for the locking member 31. The depth to which the locking surface 43 is cut is at least sufficient to form a continuous cylindrical surface. The locking surface 43 defines a hexagonal head 44 at the free end 42 of the coupling pin, the front end of the head 44 being slightly chamfered.

The portion of the plastics sheath 41 extending into the opening 23 is widened in two stages, thus facilitating insertion of the coupling pin into the opening 23. Its largest step forms a radial guide surface 45 which cooperates with the wall of the opening 23.

An outwardly directed radial shoulder 46 and an annular portion 47 of the plastics sheath 41 are contiguous to the radial guide the annular portion 47 but a plastics ring 48 is interposed therebetween. The transition piece 49 is guided on the hexagonal bar 40 by means of internal ribs 50 and is contiguous to a portion of the gardening tool head, so that, inter alia, the welded seam 39 is overlapped and the hexagonal bar 40 is fully covered in this rear region.

The plastics ring 48 forms part of a hanger and is connected to a suspension portion 52 (shown in Fig. 1) by way of two bridge portions 51 of greatly reduced cross section. This hanger can readily be made by injection moulding from plastics material, since the suspension portion 52 can be injection-moulded in the same plane as the plastics ring 48. The thin bridge portions 51 permit rotation of the suspension portion through 90 , so that the tool head can be suspended thereby. If this suspension portion should be troublesome during the subsequent use, it can readily be removed by pulling it away from the ring 48 to tear the bridge prtions 51. However, the suspension portion 52 is very advantageous for display and sales purposes, since it can carry a label and a price tag.

The embodiment of Fig. 3 differs from the embodiment of Fig. 2 in that the entire coupling pin 161 is made from plastics material. However, its design is identical to that described with reference to Fig. 1, with the sole exception that the engagement surface 43 does not comprise a cylindrical groove produced by a turning operation as in the metal embodiment, but comprises a slightly countersunk depression 431 of the same hexagonal configuration as the rest of the front portion of the coupling pin. To avoid local mass concentrations of plastics material, the cylindrical steps 53, 45, integrally formed with the hexagonal end portion of the coupling pin, and the contiguous transition portion 54, may be of hollow construction. The transition portion 54 replaces the annular portion 47, the plastics ring 48 and the transition piece 49 of Fig. 2. The coupling pin 161 made from plastics material is intended particularly for tool heads which are made from plastics material and which are not subjected to execessive stress and, preferably, may be connected to the gardening tool head 15 by means of an annular friction weld 55.

Fig. 2 shows the coupling pin 16 during insertion into the coupling sleeve comprises ing the tube 17 and the insert 19. It will be seen that insertion can be effected substantially coaxially, i.e. the central longitudinal axis 29 of the handle substantially coincides with the central longitudinal axis 56 of the coupling pin. The coupling pin can be inserted in a very simple manner, substantially smaller than that of the opening 23. The head 44 strikes against the insertion chamfer 38 substantially at the same time as the smaller step 53 enters the region of the mouth 22. This results in axial prealignment. The locating portion 24 is dimensioned such that the hexagonal portion of the coupling portion still has a relatively large amount of play therein in the direction of rotation, although the coupling pin can be pre-aligned with respect to its rotary position. Thus, the head 44 still has a considerable amount of play in the locating portion 24, and a certain amount of accurately predetermined play also still exists between the wall of the opening 23 and the radial guide surface 45 of the plastics sleeve 41 which thereupon enters the opening 23.

When, as is shown in Figs. 3 and 4, the locking member 31 is actuated by screwing in the screw 33 by turning the actuating handle 34, the screw 33 presses against the locking surface 43 and presses two of the hexagonal surfaces of the coupling pin against the contact surfaces 25. The coupling pin is thus finally secured against turning and is also forcibly secured in the direction of pull by the tightening of the screw 33 in the annular groove 43 while it is secured in the pushing direction by abutment of the end face 42 of the coupling pin against the cross member 37.

The coupling pin is thereby slightly inclined within the insert, i.e. its central axis 5(5 is at a small angle of, for example, 1.50 to the central longitudinal axis 29 of the handle. As is shown in Fig. 3, the radial guide surface 45 thus assumes a sloping position in the opening 23, such that the play previously existing between the radial guide surface and the opening is eliminated and substantially play-free guidance now exists. As may be seen, the play depends upon the axitl length of the radial guide surface and the angle of incline. Furthermore, the eccentricity of the locating portion 24 has the advantage that, by virtue of the thick wall portion 30 thus produced, the screw-thread in the plastics material can be longer, so that the screw can also withstand high stresses and frequent unscrewing and tightening. The hexagonal construction of the locking surface 431 ensures that the screw makes surface contact in the somewhat less robust plastics pin 161. In the illustrated embodiment, the locking member 31 at the same time fulfils a further function, namely that of holding the insert 19 in the tube 17 or 171. It is to be noted that the coupling pin 16, 161 is secured by frictional force, although the coupling pin is poutively prevented from slipping out by the somewhat countersunk engagement sur 43 when the locking member 31 is not iI1lY ti6htened It is advantageous to the function that the stop in the pushing direction, as well as the interior radial guide surface and the locking surface 43 for the locking member are located in the region of the free end of the coupling pin, since the locking member is scarcely stressed by bending forces acting upon the coupling, since the lever arm is very large between the radial guide surface 45 located in the region of the mouth 22 and the radial guide surfaces in the region of the head 44.

By virtue of the features of the invention it is possible to accommodate a very robust coupling in a tube having a diameter corresponding to the normal handle diameter of approximately 23 to 25 mm. By way of example, the diameter of the opening 23 can be approximately 19 mm. Play-free guidance is ensured despite the fact that the diameter of the portion 45 is approximately 1 mm smaller. The solid hexagonal bar can have dimensions of 12 mm between the faces located opposite to one another (width across flats), and the length of the portion 45 is approximately 18 mm when the length of a coupling pin to be inserted is approximately 80 mm. The surfaces 25 are subjected to the wedge action of the surfaces of the hexagonal bar so long as the bottom surface 26 of the locating portion 24 is not engaged. This can lead to additional wedging of the insert 19 in the tube 17, and may be desirable. However, by appropriate dimensioning of the surfaces 25 and 26 it is alternatively possible to provide for the head 44 to press directly against the bottom surface 26.

Fig. 5 shows a handle 111 and another embodiment of coupling 112 forming part of a gardening tool set, while Fig. 6 shows an associated coupling pin 116 which is mounted on a tool head 113 which is of the same type as the tool head 13 of Fig. 1 (i.e.

a harrow) and only a small part of which is illustrated.

The coupling illustrated in Fig. 5 has a plastics insert 119 which is inserted into the tube 117 forming the handle and which has a cylindrical coaxial opening 123 in the region of its mouth. A guide portion 160 is contiguous to the opening 123 and has inwardly projecting ribs 161 which start from the same diameter as the opening 123 and between which are formed longitudinally extending grooves 162. A cylindrical opening 163 is again formed contiguously to this relatively long guide portion.

The elongate coupling pin 116 of Fig. 6 is of corresponding construction. It has a step 145 of larger diameter which forms the radial guide surface near to the mouth, a guide portion 164 serving to prevent turning of the tool head relative to the handle, and an inner cylindrical radial guide portion 165 again contiguous to the guide por tion 164. The diameter of the cylindrical surface of the guide portion 164 is equal to that of the radial guide portion 165, i.e.

the smaller diameter, while the six proiect- ing ribs have, in conformity with the grooves 162, external dimensions equal to the diameter of the radial guide portion 145.

The described portions 145, 164, 165 are formed on an elongate sheath 141 which is made from plastics material and which is slipped onto a hexagonal metal bar 140 which is connected to a metal part of the tool head by means of a weld 139. This weld is covered by a transition and spacer piece 149 which is connected to a flanged portion 147 of the plastics sheath 141. A radial shoulder 146 is provided between the radial guide portion 145 and the flange 147 and fills in the gap in the region of the mouth 122 of the insert 119.

The free end of the coupling pin 116 has a fairly short cylindrical head which has a somewhat smaller diameter than the dimension across the flats of the hexagonal bar and which has a planar end face and a locking surface 143 in the form of a radial shoulder facing the tool head. The locking surface 143 is defined by one face of a plunge-cut annular groove 166 whose other face 167 is conically chamfered.

Fig. 5 shows the locking member 131 of the coupling 112. This locking member is a self-engaging snap coupling. The locking member 131 comprises a double-arm lever which is made from plastics material and which has at one end a sneck 168 provided with front chamfer and a substantially radial retaining surface. An actuating member 134 in the form of a push-button is formed at the other end of the double-arm lever and extends outwardly through an opening 169 in the tube 117. The double-arm lever forming the locking member is provided on each side with a laterally projecting bead 170 which forms a knife-edge bearing for the lever on a correspondingly constructed portion of the insert 119. Axial fixing in the direction of pull is effected by virtue of the fact that the locking member 131 abuts in the region of its sneck 168 against a radial surface 171 of the insert 119. A projection 172 extending into the opening 163 forms an abutment surface 173 for the head 144 of the coupling pin and receives a screw 174 which secures the insert 119 to the tube 117.

A compression spring 175 urges the actuating knob 134 outwardly and thus urges the locking member 131 into its engaged position. The locking member is only inserted into the insert and its bead is held by the tube 117. Fig. 7 shows the snap coupling of the type illustrated in Figs. 5 and 6 in its engaged state. The handle, that is the female coupling part 112, is identical to that described with reference to Fig. 5 (and is provided with the same reference numexas), while the function and the. basic sham of the coupling pin 1161 is also identical to that shown in Fig. 6, but it is. made entirely from plastics material and is injection.

moulded directly onto the tool head. 15.

(only partially illustrated). Here also, the individual parts are provided with the same: reference numerals as in Fig, 6.

It will be seen that, here also, the coupling pin 116 can be readily guided into. the handle by virtue of the fact that the. two parts are of multi-step construction, As in the embodiment described previously, the head 144 has a substantially smaller diameter than the mouth 122, so that the long coup ling pin, which is more than four times as long as its largest diameter, readily slides into the insert. Shortly before the end of this movement, it strikes against the sneck 168 and, as a result of the lead chamfer, pivots the locking member 131 in an anti clockwise direction. Just before the head 144 of the coupling pin strikes against the abutment surface 173 at the absolute end of its movement, the sneck 168 engages behind the radial locking surface 143 under the action of the spring 175 and fixes the coup ling pin in the direction of pull. The tensile force is then transmitted to the insert 119 by the shortest path, in that the front end face of the sneck 168 abuts against the radial surface 171. Thus, the mounting of the locking member 131 is not subjected to any axial force. Here also, the distance between the bridge4ike abutment surface 173 and the locking surface 143 is relatively small, so that differences in length cannot be detrimental. Prevention of turning is established by the ribs 176 in cooperation with the grooves 172, and the two portions 145, 165.

ensure satisfactory radial guidance owing to the relatively large axial distance there between.

The coupling of Figs. 5 to 7 has the advantage that it permits one-hand operation, i.e. it only has to be pushed together during the coupling operation and automatically engages. The actuating knob 134 is pressed only during the uncoupling operation in order to release the sneck 168 from the head 144. The coupling pin can then be withdrawn from the coupling sleeve.

A further embodiment of couplings is illustrated in Fig. 8. An insert 219 in the form of a plastics sleeve is provided in the tube n7 forming part of the handle and has a flange 221 which abuts against -the end of the tube. The insert 219 has an opening 223 having a regular hexagonal cross section whose dimensions are adapted to the coupling pin 216 which tis in the form of R hexagonal bar.

The coupling pin 216 is welded to a tool -head (not illustrated). The free end of the coupling pin is provided with a conical chamfer 260 which terminates at a planar end face 261. Shortly before the commencement of the chamfer 260, the coupling pin is provided with three transverse bores 262 which intersect one another, the axes of which bores are at 1200 relative to one another. Each transverse bore opens into the centre of one of the surfaces 263 of the hexagonal bar forming the coupling pin 216.

The coupling 212 of Fig. 8 is also a selfengaging snap coupling. Its locking member 231 is displaceable transversely of the insertion direction and, in the present embodiment, is in the form of substantially J- shaped member which is bent from a round steel bar and whose shorter limb 264 forms a latch portion which has a lead chamfer 265 and which is intended and dimensioned to extend into a bore 262. The bend 267 of the J-shaped member is contiguous to the limb 264 and forms a connection portion.

The other longer limb 266 is contiguous to the connection portion and extends transversely through the insert 219 and the handle. The shorter limb 264 and the longer limb 266 extend through bores 268, 269 at one side of the handle, which bores extend through the tube 217 and also through the insert 219. Thus, the connection portion 267 is located outside the handle, The longer limb 266 also extends through a bore 270 at the opposite side. The free end of the longer limb is of barb-like configuration in cross section. An actuating knob made from resilient plastics material or rubber is slipped onto the barb-like end of the longer limb and its resilient skirt 271 abuts against the exterior of the handle and pulls the locking member 231 to the position, illustrated in Fig. 8, in which the U-shaped bend 267 abuts essentially' against the side of the handle remote from the actuating knob 234, and the latch portion 264 is located in the bore 262. This construction of the actuating knob at the same time results in a satisfactory seal against the intrusion of dirt. However, it is also possible to provide a spring which assists or replaces the resilient skirt 271.

The coupling operation is effected simply by inserting the coupling pin. The hexagonal construction provides security against turning, and the elongate construction of the coupling pin secures adequate radial guidance and security against tilting.

The chamfer 260 cooperates with lead chamfer 265 of the locking member and urges the latter downwardly (as viewed in Fig. 8) against the force of the resilient skirt 271 until the latch portion 264 can engage into one of the bores 262.

The coupling is of particularly simple construction. Alternatively, the locking surfaces for the coupling, formed by the transverse bores 262, may be in the form of a continuous groove, thus preventing the coupling pin from being weakened to too great an extent at the point of engagement. The abutment in the direction of pushing is formed by the limb 266 which at the same fixes the insert 219 in an axial direction relative to the tube 217.

By virtue of the arrangement of the elongate coupling pin on the tool head, the coupling pin can also be used as a temporary handle. Advantageously, in order to further increase the versatility, it is also possible to provide several types of handles, such as a long handle for normal work and a sh

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

coupling pin is provided with a conical chamfer 260 which terminates at a planar end face 261. Shortly before the commencement of the chamfer 260, the coupling pin is provided with three transverse bores 262 which intersect one another, the axes of which bores are at 1200 relative to one another. Each transverse bore opens into the centre of one of the surfaces 263 of the hexagonal bar forming the coupling pin 216.

The coupling 212 of Fig. 8 is also a selfengaging snap coupling. Its locking member 231 is displaceable transversely of the insertion direction and, in the present embodiment, is in the form of substantially J- shaped member which is bent from a round steel bar and whose shorter limb 264 forms a latch portion which has a lead chamfer 265 and which is intended and dimensioned to extend into a bore 262. The bend 267 of the J-shaped member is contiguous to the limb 264 and forms a connection portion.

The other longer limb 266 is contiguous to the connection portion and extends transversely through the insert 219 and the handle. The shorter limb 264 and the longer limb 266 extend through bores 268, 269 at one side of the handle, which bores extend through the tube 217 and also through the insert 219. Thus, the connection portion 267 is located outside the handle, The longer limb 266 also extends through a bore 270 at the opposite side. The free end of the longer limb is of barb-like configuration in cross section. An actuating knob made from resilient plastics material or rubber is slipped onto the barb-like end of the longer limb and its resilient skirt 271 abuts against the exterior of the handle and pulls the locking member 231 to the position, illustrated in Fig. 8, in which the U-shaped bend 267 abuts essentially' against the side of the handle remote from the actuating knob 234, and the latch portion 264 is located in the bore 262. This construction of the actuating knob at the same time results in a satisfactory seal against the intrusion of dirt. However, it is also possible to provide a spring which assists or replaces the resilient skirt 271.

The coupling operation is effected simply by inserting the coupling pin. The hexagonal construction provides security against turning, and the elongate construction of the coupling pin secures adequate radial guidance and security against tilting.

The chamfer 260 cooperates with lead chamfer 265 of the locking member and urges the latter downwardly (as viewed in Fig. 8) against the force of the resilient skirt 271 until the latch portion 264 can engage into one of the bores 262.

The coupling is of particularly simple construction. Alternatively, the locking surfaces for the coupling, formed by the transverse bores 262, may be in the form of a continuous groove, thus preventing the coupling pin from being weakened to too great an extent at the point of engagement. The abutment in the direction of pushing is formed by the limb 266 which at the same fixes the insert 219 in an axial direction relative to the tube 217.

By virtue of the arrangement of the elongate coupling pin on the tool head, the coupling pin can also be used as a temporary handle. Advantageously, in order to further increase the versatility, it is also possible to provide several types of handles, such as a long handle for normal work and a short handle which makes the same tool head suitable for a special purpose, such as making a small rake suitable for use as a cemetary rake. Other implements, such as brooms and snow-shovels, can be incorporated the set in addition to gardening tools.

Attention is drawn to copending Patent Application No. 16547/77 (Serial No.

1574156) in which we have claimed a set of implements comprising at least one handle and a plurality of implement heads, there being provided a manually actuable coupling system having first and second interengageable parts, each implement head having a said first coupling part thereof and said handle having a said second coupling part thereon, whereby each implement head can be selectively attached to said handle; wherein one of the coupling parts comprises a female coupling sleeve having a movable locking member thereon and the other of said coupling parts comprises a male coupling pin having a fixed locking surface thereon with which said locking member can co-operate to lock said coupling parts together, and wherein the coupling pin is of an elongate shape so adapted to the coupling sleeve that, when the coupling pin is inserted in the coupling sleeve until a stop force on the pin engages an abutment in the coupling sleeve, the coupling pin can adopt an inclined position relative to the sleeve in which the free end portion of the pin which prevents the pin from turning in the sleeve is eccentric relative to the mating portion of the sleeve and in which radial play between an axially extending guide portion of the coupling pin remote from its free end and a corresponding axially extending guide portion in the region of the mouth of the sleeve is substantially eliminated, such radial play facilitating insertion of the coupling pin into the coupling sleeve.

forms a female coupling part on a handle,

in which the coupling pin has an elongate stepped configuration, reducing in lateral dimension towards its free end, to define at its region adjacent the implement head a radial guide portion of larger lateral dimension and at its region adjacent its free end a polygonally sectioned portion of smaller lateral dimension for preventing the coupling pin from turning in the coupling sleeve.
2. An implement as claimed in claim 1 in which the guide portion of the coupling pin is cylindrical in cross section.
3. An implement head as claimed in claim 1 or 2, in which the polygonal portion of the coupling pin is provided adjacent to the free end of the coupling pin with a locking surface adapted to be engaged by a locking member on the coupling sleeve.
4. An implement head as claimed in any preceding claim, in which the coupling pin is provided with a peripheral groove in which is defined a locking surface adapted to be engaged by a locking member on the coupling sleeve.
5. An implement head as claimed in any preceding claim, in which the free end face of the coupling pin defines an abutment to limit the extent to which the coupling pin can be pushed into the coupling sleeve.
6. An implement head as claimed in any of claims 1 to 5 in which the coupling pin is made entirely from plastics material.
7. An implement head as claimed in claim 6, which is also made from plastics material and to which the plastics coupling pin is welded.
8. An implement head as claimed in any of claims 1 to 5, in which the coupling pin comprises a metal part on which is arranged a plastics sheath which has said radial guide portion thereon.
9. An implement head as claimed in claim 8, which is made of metal and to which the metal part of the coupling pin is welded.
10. An implement head as claimed in claim 8 or 9, in which the sheath is pressed onto the metal part.
11. An implement head as claimed in claim 8, 9 or 10, in which the metal part is a polygonal bar.
12. An implement head as claimed in any of claims 8 to 11, in which the sheath has a flange adjacent the implement head.
13. An implement head as claimed in claim 12 in which the region of the metal part of the coupling pin located between the flange and the implement head is covered by a plastics shield.
14. An implement head as claimed in claim 13, in which a ring having a suspension device formed thereon is interposed between the flange of the sheath and the plastics shield.
15. An implement head as claimed in claim 14, in which the suspension device has, adjacent to the ring, two reduced dimension bridge portions which are located opposite to one another and which act as pivots.
16. An implement head as claimed in claim 15, in which the bridge portions define fracturing locations at which the suspension device can be broken away.
17. An implement head as claimed in any of claims 1 to 16, in which the polygonal portion of the coupling pin has a regular hexagonal cross section.
18. An implement head as claimed in any of claims 1 to 16, in which said polygonal portion of the coupling pin has outwardly projecting longitudinal ribs for preventing the coupling pin from turning.
19. An implement as claimed in any of claims 1 to 16 or in claim 18 in which the coupling pin has a radial guide portion at or near its free end.
20. An implement head as claimed in claim 19, in which the polygonal portion of the coupling pin for preventing the coupling pin from turning is arranged between the axially spaced radial guide portions.
21. An implement head as claimed in any of claims 1 to 16 or in claim 18, 19 or 20, in which a small head is formed at the free end of the coupling pin and its shoulder directed away from the free end forms a locking surface adapted to be engaged by a locking member on the coupling sleeve.
22. An implement head as claimed in claim 2 in which the radial guide portion is defined by plastics material.
23. An implement head provided with a coupling pin constructed substantially as herein described with reference to and as illustrated in Figs. 1 and 2 of the accompanying drawings.
24. An implement head provided with a coupling pin constructed substantially as herein described with reference to and as illustrated in Figs. 3 and 4 of the accompanying drawings.
25. An implement head provided with a coupling pin constructed substantially as herein described with reference to and as illustrated in Fig. 6 of the accompanying drawings.
26. An implement head provided with a coupling pin constructed substantially as herein described with reference to and as illustrated in Fig. 7 of the accompanying drawings.
27. An implement head provided with a coupling pin constructed substantially as herein described with reference to and as illustrated in Fig. 8 of the accompanying drawings.
28. An implement head as claimed in any preceding claim which is a gardening tool head.