GB2079350A - Mounting means for mineral cutting picks - Google Patents

Abstract

A mineral cutting pick provided with resilient means (22) for retaining it in a socket in pick box (16). So that the force required to insert the pick in the pick box can be relatively small and the force required to extract it can be relatively high, the resilient means (22) include projecting parts (24) which take up positions in the pick box from which they cannot be returned by an extraction force applied to the cutter pick. An extraction force applied to the pick is effective to at least partially shear or rupture the projecting parts (24) of the resilient means from the part of said means connected to the pick or to invert said projecting parts (24) to allow the extraction of the pick from the pick box. Other forms of resilient means 22 to that shown in Figure 1 are also described. <IMAGE>

Description

SPECIFICATION Mounting means for mineral cutting picks The invention relates to mounting means for mineral cutting picks and has for its object to provide an improvement therein.

It is known to retain a cutter pick with a noncircular shank in a pick box by resilient means housed in a recess adjacent the end of the pick shank, the resilient means including projections with toothed or stepped surfaces extending from opposite sides of the shank and adapted to spring apart when the pick shank has been fully inserted into the pick box and to engage with a cutaway part of the pick box, the arrangement being such that when it has subsequently been desired to extract the cutter pick from the pick box a sufficient extraction force applied to the cutter pick has caused the resilient means to be delected to such an extent as to be disengaged from the cutaway part of the pick box.

Such previously known mounting means have generally worked quite well initially although they do sometimes suffer from certain disadvantages. For example, the projections have been prone to wear if the pick shank and the aperture in the pick box have become worn to such an extent as to allow rocking movements of the pick relative to the pick box to take place. If this occurs it can cause "fretting" of the resilient means referred to and there is the danger of the pick being ejected from the pick box during a cutting operation. Furthermore, depending upon the degree by which the projections spring apart into engagement with the cutaway part of the pick box, the resilient retaining means can sometimes have only a tenuous hold in the pick box, again with the attendant risk that the pick might be ejected from the pick box during a cutting operation.Even if such previously known mounting means have worked entireiy as designed to do, the required insertion force has been somewhat higher than is desirable and the force required to extract the pick for replacement by a new pick has been somewhat less than is now thought desirable.

It is also known to retain a cutter pick with a circular shank in a pick box by either a circlip or a resilient ring engaged in a groove adjacent the end of the pick shank. However, difficulties have also been found in the operation of these known retaining means, notably the difficulty of pick extraction when the circlip or resilient ring has become covered in dirt and the like. The invention aims to provide a mounting means for a mineral cutting pick which will at least alleviate the disadvantages referred to above.

According to one aspect of the invention, there is provided a mineral cutting pick with a shank for fitment in a complementary socket in a pick box, the pick being provided with resilient means for retaining it in said socket, that is to say means which when the pick shank is being inserted into the socket are inwardly deformed by the walls of the socket to allow the insertion of the shank, the resilient means being such that when the shank has been fully inserted into said socket said resilient means have been able to spring outwards again to such an extend as to engage either a cutaway part of the pick box or a back face of the pick box, as the case may be, the resilient means taking up positions from which they cannot be returned by an extraction force applied to the cutter pick, the resilient being being such that an appropriate extraction force applied to the pick is sufficient to at least partially shear or rupture the projecting parts of the resilient means from the part of said means connected to the pick or to invert said projecting parts with respect to the part connected to the pick to allow the extraction of the pick from the pick box.When the pick has a non-circular shank for fitment in a complementary socket in a pick box, the resilient means may be constituted buy a resilient element which has a pair of oppositely disposed wedge members connected together by means of a cross piece accommodated in a slot extending across one side surface of the shank, the arrangement being such that when the pick is to be fitted in the pick box, the shank is entered into the socket and the wedge members of the resilient element are deflected inwardly as they ride down opposite side surfaces of said socket, said wedge members being able to spring outwardly into locking engagement with the pick box as the shank becomes fully inserted in said socket.Alternatively, the resilient means may be constituted by a pair of resilient elements which can be placed in position on opposite sides of the pick shank, said elements each being provided with a projecting plug portion which can be inserted into a cross bore in the shank, the plug portions of the resilient elements being accommodated at least in part in overlapping relation in said cross bore and and having snap action interconnection one with the other so that the resilient means can very simply be connected to the pick shank before the latter is entered into the socket in the pick box.In this case, the wedge members may be provided with laterally extending resilient leaf elements arranged to bear at their opposite ends against spaced apart side surfaces of the pick shanks, said leaf elements being arranged to urge the wedge members outwards to engage the cutaway part of the pick box or the back surface of the pick box, as the case may be.On the other hand, the pair of resilient elements may be connected together by an integral strut element at their ends remote from the projecting plug portions, the pair of resilient elements and said integral strut element having been moulded with said resilient elements at an angle one to the other, the arrangement being such that in being connected to a pick shank by their plug portions being inserted into the opposite ends of the cross bore therein the resilient elements impose a bending action on the integral strut element so that this brings about the required tendency for the wedge members to be urged outwards away from the pick shank and into engagement with the cutaway part of the pick box or the back face of the pick box, as the case may be.The wedge members may be provided with resilient trailing elements arranged to act against the walls of the socket at the pick is being fitted in position, said trailing elements acting with a lever action to force the wedge members outwards into engagement with the cutaway part of the pick box or the back face of the pick box as the case may be. When the pick has a circular shank for fitment in a socket of cylindrical shape, the resilient means may be constituted by a resilient element in the form of an annular collar or C-clip element engageable in a groove adjacent the end of the pick shank remote from the head of the pick, the annular collar or C-clip being provided at least around the outer periphery with a plurality of resilient wedge members.If the resilient element is an annular collar, it may have a plurality of resilient wedge members around its inner periphery also, these being for the purpose of enabling the element to be engaged in a groove adjacent the end of the pick shank. If the resilient element is in the nature of a C-clip, the inner periphery of the C-ciip may be provided with a plurality of spaced spring pieces arranged to bear radially inwardly against the bottom of the groove in the pick shank, whereby the C-clip is capable of being inwardly deformed by the walls of a socket in a pick box in which the pick is being fitted, but whereby the C-clip is maintained substantially co-axiaily of the pick shank as it becomes able to spring outwards as its resilient wedge members engage the cutaway part of the pick box or the back face of the pick box, as the case may be.A resilient element, in the form of a C-ciip, may be provided at the opposite extremities of the C with small holes capable of being engaged by the nose portions of the jaws of a circlip fitment tool. If the projecting parts of the resilient means are arranged, on the extraction of the pick from the pick box, to be at least partially sheared or ruptured from the part of said means connected to the pick, a flexible safety link will preferably be provided between each projecting part and said part connected to the pick so that on the removal of the pick from the pick box the sheared or ruptured parts are extracted from the pick box.If the resilient means are made largely of a synthetic plastics material, shoulder portions of the projecting parts of the resilient means will peferably be provided with metal reinforcement at surfaces which, when the pick shank has been fully inserted into a socket in a pick box, bear against a cutaway part of the pick box or a back face of the pick box as the case may be.

According to a further aspect of the invention, there is provided a mineral cutting pick and box therefor, the pick being provided with resilient means as described above for retaining it in said pick box.

In order that the invention may be fully understood and readily carried into effect, the same will now be described, by way of example only, with reference to the accompanying drawings, of which: Figure 1 is a schematic drawing illustrating a mineral cutting pick embodying the invention and pick box therefor, Figure 2 is a sectional view on the line 2-2 in Figure 1 with the pick shank entered fully into said pick box, and Figures 3to 19 are views which will presently be referred to when describing possible modifications.

Referring now to Figures 1 and 2 of the drawings, the mineral cutting pick generally indicated 10 has a shank 12 of generally rectangular cross section for fitting non-rotatably in a socket 14 in a pick box 16, the latter being welded at its root end to a drum or cutter head (not shown) of a mineral mining machine. Adjacent the free end of the pick shank, that is to say the end remote from a head portion 13, there is provided a slot 15 for a purpose which will presently be explained.The socket 14 in the pick box is of complementary shape to the generally rectangular cross sectional outline shape of the pick shank except that, as shown in Figure 1, it is provided with shallow part circular grooves 18 which extend along opposite side surfaces of the socket, this resulting from the fact that the pick receiving socket in a pick box of this known kind is made by drilling a hole and then carrying out a broaching operation to produce the required rectangular part of the socket. An aperture 20 which extends across the root end of the pick box intersects the socket 14 at the end of the latter remote from the end at which the pick shank is to be entered in said aperture.

Means which are provided for retaining the pick shank in the socket during a mineral mining operation are constituted by a resilient element generally indicated 22 which has a pair of oppositely disposed wedge members 24, connected together by means of a cross piece 26.

When the pick is to be fitted in the pick box, the resilient element 22 is connected to the free end of the pick shank by its cross piece 26 being entered into the slot 15 in said shank. The shank is then entered into the socket in the pick box, as indicated diagrammatically in Figure 1, the wedge members 24 being deflected inwardly as they ride down the surfaces of the grooves 18 of the socket. As the shank becomes fully inserted in the socket, the wedge members are able to spring outwardly into the aperture 20 at the root end of the pick box so that, resulting from the slope on the top surfaces of said wedge members, a cam action takes place which tends to pull the pick down fully into the pick box and to retain it therein during a cutting operation.As shown in Figure 2, when the shank has been fully inserted into the socket the resilient means have been able to spring outwards again to such an extent as to be incapable of being returned to their former positions in close contact with the pick shank by an extraction force applied to the pick.

When it is subsequently desired to remove the pick from the pick box, so that it can be replaced by a new pick, an extraction force is applied to the pick sufficient to shear the wedge members 24 from the cross piece 26 of the resilient element 22. The shank of the pick can then be extracted from the socket with the cross piece 26 still located in the slot in the shank; the wedge members 24 will harmlessleyfall from the pick box through the aperture 20 (or through the aperture 14 if the pick box happens to be in inverted condition).It will be understood that depending on the dimensions of the resilient element at the points where it is to be sheared (and these can of course be determined by trial and experiment) the extraction force required to remove the pick from the pick box can be predetermined and can be arranged to be quite substantial to obviate any chance of the pick becoming detached from the pick box by inadvertence.

Referring now to Figures 3 and 4 of the drawings, in a somewhat different embodiment of the invention the shank 12 of the mineral cutting pick, again of generally rectangular cross section for fitting in a pick box such as that illustrated in Figure 1, is again provided with resilient means for retaining the pick shank in its socket, but in this case said resilient means are constituted by a pair of resilient elements 28 placed in position on opposite sides of the pick shank. The resilient elements 28 are each provided with a projecting plug 30 which can be inserted into a cross bore 32 in the pick shank, each plug being provided with a hook-like end 34, the arrangement being such that the plug portions are accommodated in partly overlapping relation, having snap action interconnection one with the other.

Referring in particular to Figure 4, it will be seen that the resilient elements 28 are formed with wedge members 36 at their lower ends, the inner portions of said wedge members being formed as relatively thin membranes 38 having overlying flap portions 40. When the pick shank has been fully inserted in its socket, the wedge members become immovably located within the aperture 20 at the root end of the pick box with the flap portions 40 at such a shallow angle, as shown, that the wedge members cannot possibly release themselves when an extraction force is applied to the pick.It will be understood that when the pick shank is entered into its socket the membrane portions 38 of the wedge members are able to resiliently fold to some extent to allow the entry of the wedge members, but when an extraction force is applied to the pick the tendency is for the membrane portions to be stretched. In the result the application of an adequate extraction force results in the membrane portions being at least partially sheared off to allow the flap portions 40 to collapse inwards or to fall away and release the pick from the pick box.

In Figure 5 there is illustrated a possible modification of the embodiment just described, the modification being the addition of resilient trailing elements 41 to the overlying flap portions 40 of the wedge elements. It will be seen that in their free condition to the trailing elements diverge from the resilient elements 28 which are adapted to lie against the side surfaces of the shank of a pick. The arrangement is such that as the pick is being fitted in position, said trailing elements act with a lever action to force the wedge members outwards into engagement with the cutaway part of the pick box or the back face of the pick box as the case may be. It will be noted that the membranes 38 are shown to have been retained in the modification illustrated in Figure 5, but it may be found that the membranes are not required, particularly in this modified arrangement.

In Figures 6 to 8 there is illustrated an arrangement very similar to that just described, that is to say in the fact that it includes a pair of resilient elements 20 formed with wedge members 36 at their lower ends, the resilient elements also being provided with projecting plugs 30 which can be inserted in a cross bore in the pick shank and snap action interconnection. However, in this case the wedge members are provided with laterally extending resilient leaf elements 42 arranged to bear at their opposite ends against spaced apart side surfaces 44 of the pick shank, said leaf elements being arranged to urge the wedge members outwards to engage the cutaway part of the pick box or the back face of the pick box as the case may be.It will be seen that in this case the shank of the pick has been provided with depressions 46 on its opposite side surfaces into which the wedge members can be deflected as the shank is being entered into the socket in the pick box.

Referring now to Figures 9 to 11 in another arrangement very similar to that described in Figures 3 and 4 the pair of resilient elements 20 have been connected together at their ends remote from the projecting plug portions 30 by an intergral strut element 48. As indicated in Figure 11 the pair of resilient elements and the integral strut element 48 have been moulded integrally together with the resilient elements at an angle one to the other, the arrangement being such that in being connected to the pick shank by their plug portions being inserted into the opposite ends of the cross bore therein the resilient elements impose a bending action on the integral strut element as indicated by the chaindotted lines in Figure 11; this brings about the required tendency for the wedge members to be urged outwards away from the pick shank and into engagement with the cutaway part of the pick box or the back face of the pick box as the case may be.

In Figure 12 there is illustrated a possible modification which is applied to any one of the arrangements illustrated in Figures 3 to 11, this being a modification to the hook-like ends 34 of the projecting plug portions 30 so that, the interconnecting surfaces 50 being inclined, the engagement of the plug portions can take up any variation in the thickness of the pick shank at that point.

Referring now to Figures 13 and 14 in a further embodiment of the invention a pick with a circular shank 52 is shown to be retained in a socket 54 of cylindrical shape in a pick box 56. In this case the means which are provided for retaining the pick in the pick box during a mineral mining operation are constituted by a resilient element 58 in the form of an annular collar engageable in a groove adjacent the end of the pick shank remote from the head of the pick. The resilient element 58 is provided, as shown, with a plurality of equally spaced wedge members 60 around its interior circumference and a plurality of similarly spaced wedge members 62 around its exterior circumference. The wedge members 60 and 62 take the form of resilient flap elements 64 connected to the opposite ends of the annular collar and having collapsible membranes 66 allowing the folding of said flap elements against said collar but limiting their movement away from said collar.

In use, when the pick shank has been entered into the socket in the pick box the resilient means referred to, that is to say the wedge members 62, have been able to fold inwards by the partial collapse of their adjoining membranes 66 to allow the insertion of the shank and, when the shank has been fully inserted, have been able to spring outwards against to such an extent as to engage the back face of the pick box. As in the case of the previously described embodiment, the wedge members cannot possibly release themselves when an extraction force is applied to the pick, but when an adequate extraction force is applied to the pick the membrane portions 66 are at least partially sheared off or ruptured to allow the resilient flap elements 62 or 64 to invert themselves or fall away and release the pick from the pick box.

It is thought that the various means referred to herein for retaining a pick shank in its socket will be a considerable improvement on such means previously employed. Firstly, it is thought that the retaining means embodying the invention will be safer than such means previously employed, this being because movement of the shank in its socket will not cause "fretting" of the retaining means. Secondly, by trial and experiment it has been possible to design the retaining means so that a relatively low insertion force is required when entering the pick shank into its socket but so that a relatively high extraction force is required to remove the pick for replacement by a new pick.

Various other modifications may be made. For example, it is possible that the resilient retaining means for holding a pick shank of rectangular section could act at one side only of the pick shank.

In the embodiment illustrated in Figures 3 and 4 the wedge members are shown to be below the cross bore in the pick shank. However, it would be possible for this arrangement to be inverted, that is to say for the wedge members to be located above the cross bore and nearer the head of the pick (and of course in this case the cutaway part of the pick box with which the wedge members are to be engage would be appropriately re-located). It will also be understood that the wedge members illustrated in Figures 3 and 4 could be differently formed. For example, the membranes 38 could be differently located, that is to say they could occupy a horizontai plane instead of a vertical plane as illustrated.

Referring now to Figures 15 and 16, these illustrate an alternative form of retaining means for holding a pick with a circular shank, that is to say a resilient retaining element moulded in a synthetic plastics material or made of spring steel and having the form of a C-clip engageable in a groove adjacent the end of the pick shank. in this case, the retaining element does not need to have a plurality of resilient wedge members around its inner periphery because its engagement in the groove in the pick shank can be effected by springing open the C-clip. However, it will be seen that the retaining element illustrated in Figures 15 and 16 is provided with three spaced spring pieces 68 arranged to bear radially inwardly against the bottom of the groove in the pick shank.

The arrangement is such that the C-clip is capable of being inwardly deformed by the wall of the socket in a pick box in which the pick is being fitted, but is maintained substantially co-axial of the pick shank as it becomes able to spring outwards as its resilient wedge members engage a cutaway part of the pick box or the back face of the pick box, as the case may be. (It will be seen in Figure 16 that the outwardly projecting parts of the C-clip are in this case seven in number but it will be understood that they could be any convenient number from two upwards.

In Figures 17 and 18 there is illustrated a form of retaining means rather similar to that just described, that is to say in the fact that it is a resilient retaining element in the form of a C-clip. However, in this case the retaining element is formed of spring steel and the opposite extremities of the C are shown to be provided with small holes 70, these being for the engagement of the nose portions of the jaws of a circlip fitment tool (not shown) by means of which the retaining element can be sprung open for fitment; to the shank of a mineral cutting pick.It will be understood that when the shank of the pick is being entered into the socket of a pick box, the outwardly projecting parts of the C-clip are able to be deformed very slightly inwardly, as shown in chain-dotted lines in Figure 18, within the elastic limit of the material, but that when an extraction force is subsequently applied to the pick, the outwardly projecting parts are inverted, also as shown in chain-dotted lines in Figure 18, this being a deformation beyond the elastic limit of the material so that the C-clip is then discarded along with the worn pick.

When the resilient means are made largely of a synthetic plastics material, shoulder portions of the projecting parts may be provided with metal reinforcement at surfaces which when the pick shank has been fully inserted into a socket in a pick box, bear against a cut-away part of the pick box or a back face of the pick box, as the case may be. This is illustrated in Figure 19 where resilient means, rather similar to those previously described with reference to Figures 3 and 4, are provided with wedge members having shoulder portions reinforced by metal pins 72. Also illustrated in Figure 19 is the provision of a flexible safety link 74 between the projecting part, that is to say the wedge members, the part 28 connected to the pick.The arrangement is such that on the removal of the pick from the pick box, the sheared or ruptured parts are extracted from the pick box so that they cannot interfere with the subsequent fitment of a new pick.

It has been found that in particularly arduous operating conditions the resilient wedge members can become deformed by fatigue to such an extent that there is a danger of the pick becoming released from the pick box. Consequently, it is proposed that in the case of a resilient element in the form of an annular collar or C-clip element for retaining a circular shank cutting pick in its socket, two sets of resilient wedge members may be provided, the abutment surfaces of one set being slightly displaced, axially of the collar or C-clip, with respect to the abutment surfaces of the other set. In thise case the arrangement would be such that when one set of wedge members becomes deformed byfatiguethe other set becomes operable by bearing against the cutaway part of the pick box or the back face of the pick box, as the case may be.

Claims (14)

1. A mineral cutting pick with a shank for fitment in a complementary socket in a pick box, the pick being provided with resilient means for retaining it is said socket, that is to say means which when the pick shank is being inserted into the socket are inwardly deformed by the walls of the socket to allow the insertion of the shank, the resilient means being such that when the shank has been fully inserted into said socket said resilient means have been able to spring outwards again to such an extent as to engage either a cutaway part of the pick box or a back face to the pick box, as the case may be, the resilient means taking up positions from which they cannot be returned by an extraction force applied to the cutter pick, the resilient means being such that an appropriate extraction force applied to the pick is sufficient to at least particlly shear or rupture the projecting parts of the resilient means from the part of said means connected to the pick or to invert said projecting parts with respect to the part connected to the pick to allow the extraction of the pick from the pick box.

2. A mineral cutting pick having a non-circular shank for fitment in a complementary socket in a pick box, in combination with resilient means for retaining the pick shank in said socket, according to claim 1, said resilient means being constituted by a resilient element which has a pair of oppositely disposed wedge members connected together by means of a cross piece accommodated in a slot extending across one side surface of the shank, the arrangement being such that when the pick is to be fitted in the pick box, the shank is entered into the socket and the wedge members of the resilient element are deflected inwardly as they ride down opposite side surfaces of said socket, said wedge members being able to spring outwardly into locking engagement with the pick box as the shank becomes fully inserted in said socket.

3. A mineral cutting pick having a non-circular shank for fitment in a complementary socket in a pick box, in combination with resilient means for retaining the pick shank in said socket, according to claim 1, said resilient means being constituted by a pair of resilient elements which can be placed in position on opposite sides of the pick shank, said elements each being provided with a projecting plug portion which can be inserted into a cross bore in the shank, the plug portions of the resilient elements being accommodated at least in part in overlapping relation in said cross bore and having snap action interconnection one with the other so that the resilient means can very simply be connected to the pick shank before the latter is entered into the socket in the pick box.

4. The mineral cutting pick and retaining means combination according to claim 3, in which the wedge members are provided with laterally extending resilient leaf elements arranged to bear at their opposite ends against spaced apart side surfaces of the pick shank, said leaf elements being arranged to urge the wedge members outwards to engage the cutaway part of the pick box or the back surface of the pick box, as the case may be.

5. The mineral cutting pick and retaining means combination according to claim 3, in which the pair of resilient elements are connected together by an integral strut element at their ends remote from the projecting plug portions, the pair of resilient elements and said integral strut element having been moulded with said resilient elements at an angle one to the other, the arrangement being such that in being connected to a pick shank by their plug portions being inserted into the opposite ends of the cross bore therein the resilient elements impose a bending action on the integral strut element so that this brings about the required tendency for the wedge members to be urged outwards away from the pick shank and into engagement with the cutaway part of the pick box or the back face of the pick box, as the case may be.

6. The mineral cutting pick and retaining means combination according to any one of claims 2 to 5, in which the wedge members are provided with resi lienttrailing elements arranged to act against the walls of the socket as the pick is being fitted in position, said trailing elements acting with a lever action to force the wedge members outwards into engagement with the cutaway part of the pick box or the back face of the pick box as the case may be.

7. A mineral cutting pick having a circular shank for fitment in a socket of cylindrical shape, in combination with resilient means for retaining the pick shank in said socket, according to claim 1, the resilient means being constituted by a resilient element in the form of an annular collar or C-clip element engageable in a groove adjacent the end of the pick shank remote from the head of the pick, the annular collar or C-clip being provided at least around the outer periphery with a plurality of resilient wedge members.

8. The mineral cutting pick and retaining means combination according to claim 7, in which the resilient element is an annular collar and has a plurality of resilient wedge members arounds its inner periphery also, these being for the purpose of enabling the element to be engaged in a groove adjacent the end of the pick shank.

9. The mineral cutting pick and retaining means combination according to claim 7, in which the resilient element is in the nature of a C-clip the inner periphery of which is provided with a plurality of spaced spring pieces arranged to bear radially inwardly against the bottom of the groove in the pick shank, whereby the C-clip is capable of being inwardly deformed by the walls of a socket in a pick box in which the pick is being fitted, but whereby the C-clip is maintained substantially co-axial of the pick shank as it becomes able to spring outwards as its resilient wedge members engage the cutaway part of the pick box or the back face of the pick box, as the case may be.

10. The mineral cutting pick and retaining means combination according to either one of claims 7 and 9, in which the resilient element, in the form of a C-clip, is provided at the opposite extremities of the C with small holes capable of being engaged by the nose portions of the jaws of a circlip fitment tool.

11. The mineral cutting pick and retaining means combination according to any one of claims 7 to 10, the annular collar or C-clip, as the case may be, being provided around its outer periphery with two sets of resilient wedge members the abutment surfaces of one set being slightly displaced, axially of the collar or C-clip, with respect to the abutment surfaces of the other set, the arrangement being such that, in use, when one set of said wedge members becomes deformed by fatigue the other set becomes operable by bearing against the cutaway part of the pick box or the back face of the pick box, as the case may be.

12. The mineral cutting pick and retaining means combination according to any one of the preceding claims, in which the projecting parts of the resilient means are arranged, on the extraction of the pick from the pick box, to be at least partially sheared or ruptured from the part of said means connected to the pick, a flexible safety link being provided between each projecting part and said part connected to the pick so that on the removal of the pick from the pick box the sheared or ruptured parts are extracted from the pick box.

13. The mineral cutting pick and retaining means combination according to any one of the preceding claims, in which the resilient means are made largely of a synthetic plastics material, shoulder portions of the projecting parts of the resilient means being provided with metal reinforcement at surfaces which, when the pick shank has been fully inserted into a socket in a pick box, bear against a cutaway part of the pick box or a back face of the pick box, as the case may be.

14. A mineral cutting pick with resilient means for retaining it in a socket in a pick box, substantially as hereinbefore described with reference to and as illustrated by Figures 1 and 2, Figures 3 and 4, Figure 5, Figures 6 to 8, Figures 9 to 11, Figure 12, Figures 13 and 14, Figures 15 and 16, Figures 17 and 18 or Figure 19 of the accompanying drawings.