GB2195132A

GB2195132A - Tool locking

Info

Publication number: GB2195132A
Application number: GB08709967A
Authority: GB
Inventors: Alexander Brian Graham
Original assignee: WIMET MINING Ltd
Current assignee: WIMET MINING Ltd
Priority date: 1986-04-28
Filing date: 1987-04-28
Publication date: 1988-03-30
Also published as: GB8610330D0; GB2195132B; GB8709967D0

Abstract

A cutting tool and a carrier for the tool are assembled together with one part having an aperture (4) in which a projecting member of the other part is inserted. A locking member (6) of the assembly is inserted in an opening (8) in the one part extending transversely to and intersecting the aperture in that part to engage with the other part located in that aperture. The lock member comprises an elastomeric body (12) that projects into lateral regions of the opening at opposite sides of the aperture, and a locking element (10) secured to the body to extend into the aperture and engage the other part of the assembly therein. At the opening lateral regions, the elastomeric body has projections to hold the locking member in place, these projections being shown as circumferential ribs that are deformed by engagement with the walls of the opening and provide a frictional grip retaining the locking member in place. <IMAGE>

Description

SPECIFICATION Tool locking This invention relates to tools and tool holders for purposes such as breaking or excavating, and has applications in fields such as mining, construction and civil engineering apparatus, such as coal cutting machines.

According to one aspect of the invention, there is provided an assembly comprising a cutting tool and a tool carrier, of said two parts of the assembly one comprising an aperture and the other part comprising a projecting member inserted in said aperture, said parts being held together by means comprising a locking member inserted in an opening in said one part extending transversely to and intersecting said aperture, the locking member comprising an elastomeric element projecting into lateral regions of the opening at opposite sides of said aperture and a locking element secured to the elastomeric element and extending into the aperture to engage the projecting member of said other part of the assembly therein, the element having elastically deformable peripheral projections that are engaged by said one part in or adjacent said regions of the opening to hold the locking member in the opening.

According to another aspect of the invention, there is provided means for holding a cutting tool and a tool carrier in assembly with each other, of said two parts of the assembly one comprising an aperture and the other part comprising a projecting member inserted in said aperture, the holding means comprising a locking member inserted in an opening in said one part extending transversely to and intersecting said aperture, the locking member comprising an elastomeric element projecting into lateral regions of the opening at opposite sides of said aperture and a locking element secured to the elastomeric element and extending into the aperture to engage the projecting member of said other part of the assembly therein, at least said lateral regions the elastomeric element having peripheral projections that are deformed by engagement with the walls of said regions of the opening to grip the locking member in the opening.

In one configuration the tool carrier comprises said aperture and a shank of the tool is inserted in the aperture to secure the tool in the carrier. Alternatively the tool carrier can comprise a spigot-like extension on which the tool is mounted through a socket in its shank.

Preferably, said peripheral projections of the elastomeric element are in the form of series of ribs, running circumferentially.

By way of example, the invention will be described in more detail with reference to the accompanying drawings, wherein: Fig. 1 is a longitudinal section of a locking member on line I-I in Fig. 2, showing it mounted in an assembly according to the invention, Fig. 2 is a cross-section of the locking member on the line ll-ll in Fig. 1, and Fig. 3 is a detail sectional illustration of the projections on the locking member of Figs. 1 and 2.

The drawings show only fragmentarily the carrier 2 of a cutting tool holder, which comprises a conically tapered bore 4 to receive a generally known corresponding form of shank of a coal cutter pick (not shown). A locking member 6 is inserted in an opening 8 transverse to and intersecting the tool shank bore 4 to hold the pick in the carrier after its shank has been inserted in the bore.

The locking member comprises a rigid e.g.

steel, pin 10 bonded to a resilient body 12, e.g. of neoprene, to lie at one side of the body, which projects beyond the ends of the pin. Apart from ribbed end regions 14 on the resilient body, the member 6 has a uniform cross-section composed of the smaller radius of the locking pin 10 and the larger radius of the resilient body 12 backing the pin, with transition regions 16 between them that may be tapered, as shown, or parallel. The opening 8 into which the locking member is inserted can have a similar elongated cross-section, with a smaller radius portion slightly larger than the pin radius and a larger radius portion of a size between the crest and root radii of the ribbed end regions 14. At the ribbed end regions 14 themselves these larger and smaller radius portions of the'member cross-section are provided by the resilient body.

The ribbed regions 14 extend from the ends of the locking member and overlap the ends of the rigid locking element 10. The ribs 18 of the end regions run circumferentially around the larger radius portion of the body crosssection but terminates at the smaller radius portion in the end regions. The ribs have a butress-form cross-section preferably, with the perpendicular or near perpendicular faces 20 directed towards the opposite end of the locking member.

Since the ribs 18 in their free state extend to a greater radius than the opening 8, they are deformed by engagement with the walls of the opening to provide a frictional grip between the body and the opening retaining the member in place. The resiiience of the body ensures that the pin is normally held against the adjacent peripheral face of the opening, projecting into the tool shank bore. Because of the inward inclination of the rib profiles, there is greater resistance to accidental displacement of the locking member from the opening.

In use, with the aid of an entry chamfer 22, the locking member is pushed into position in the tool carrier so that the pin 10 projects into the bore 4 for the tool shank; the fit is such that considerable force is needed to insert the member. When a tool shank is pressed into the bore, the shank pushes the pin away radially with deformation of the resilient body 12 until the tool reaches its fully inserted position when a recess on the shank comes into register with the pin which is then resiliently urged into the recess to lock the tool in place.

The central portion of the resilient body is displaced by the deflection of the pin 10 from the bore 4, as occurs when a tool shank is inserted in or removed from the bore. The body is pressed against the opposed face of the opening and offers significant resistance to the displacement, so ensuring that when the inserted tool is operating the pin will not release the shank because of any minor axial forces that the tool may experience. In fact, because the pin projects into the gripping end portions 14 of the resilient body, these offer a considerable resistance to any radial movement of the pin by forces transmitted through the pick shank. Rotation of the locking member is precluded by its elongated cross-section.If it is desired to reduce the retaining forces on the tool shank, to make replacement of the tool easier, the resilient body can be given one or more reliefs, e.g. on the face diametrically opposite to the bore 4.

The gripping ribs may be extended beyond the end portions, into the central portion of the body between these, although it would not be an advantage to cause too great an increase in resistance to displacement of the pin when a pick shank is being inserted into the carrier bore.

The resilient body is shown projecting from the ends of the opening and, if desired, the end rib that lie free of the opening can be enlarged to form heads that can bear against the end faces into which the opening breaks so as to hold the locking member against displacement from the aperture. It is possible to dispense with the gripping ribs altogether if such resilient heads or end projections beyond the ends of the opening can retain the locking member in place sufficiently securely.

It will be understood that if the tool holder is provided with a tapered spigot in a tool carrier, on which a cutter pick is mounted by a corresponding tapered bore in the rear of its shank, the illustrated locking means can be similarly employed tQ secure the tool and carrier together.

Claims

1. An assembly comprising a cutting tool and a tool carrier, of said two parts of the assembly one comprising an aperture and the other part comprising a projecting member inserted in said aperture, said parts being held together by means comprising a locking member inserted in an opening in said one part extending transversely to and intersecting said aperture, the locking member comprising an elastomeric element projecting into lateral regions of the opening at opposite sides of said aperture and a locking element secured to the elastomeric element and extending into the aperture to engage the projecting member of said other part of the assembly therein, the element having elastically deformable peripheral projections that are engaged by said one part in or adjacent said regions of the opening to hold the locking member in the opening.

2. An assembly according to claim 1 wherein said peripheral projections comprise at least one projection disposed within said opening to be deformed by engagement with the walls of said lateral regions of the opening and provide a frictional retaining force for the locking member therewith.

3. An assembly according to claim 1 or claim 2 wherein said peripheral projections comprise at least one projection lying outside the opening and being restrained from withdrawal through the opening by engagement with an end face of the opening.

4. An assembly comprising a cutting tool and a tool carrier, of said two parts of the assembly one comprising an aperture and the other part comprising a projecting member inserted in said aperture, said parts being held together by means comprising a locking member inserted in an opening in said one part extending transversely to and intersecting said aperture, the locking member comprising an elastomeric element projecting into lateral regions of the opening at opposite sides of said aperture and a locking element secured to the elastomeric element and extending into the aperture to engage the projecting member of said other part of the assembly therein, at least said lateral regions of the elastomeric element having peripheral projections that are deformed by engagement with the walls of said regions of the opening to grip the locking member in the opening.

5. An assembly according to any one of the preceding claims wherein the peripheral projections within the opening are in the form of circumferential ribs.

6. An assembly according to any one of the preceding claims wherein the projections have perpendicular or near perpendicular side faces directed towards the opposite end region of the locking member.

7. An assembly according to any one of the preceding claims wherein the resilient body extends beyond the ends of the locking element.

8. An assembly according to claim 7 wherein the lateral regions occupied by the peripheral projections overlap opposite ends of the locking element.

9. An assembly according to any one of the preceding claims wherein the locking element within the opening has a substantially uniform cross-section transverse to the axis of the opening.

10. An assembly according to claim 9 wherein the locking member and the opening have non-circular cross-sections that prevent rotation of the member in the opening.

11. An assembly according to any one of the preceding claims wherein the tool carrier comprises said aperture and a shank of the tool is inserted in the aperture to secure the tool in the carrier.

12. An assembly according to any one of claims 1 to 10 wherein the tool carrier comprises a spigot-like extension and the tool has a shank provided with a socket through which the tool is mounted on said extension.

13. A locking member for an assembly according to any one of the preceding claims.

14. An assembly of cutting tool, tool carrier and locking member constructed and arranged for use substantially as described herein with reference to the accompanying drawings.

15. A locking member for holding a cutting tool and a tool carrier in assembly with each other, constructed and arranged for use substantially as described herein with reference to the accompanying drawings.