Chucks or sockets – With fluid-pressure actuator – Radially reciprocating jaws
Reexamination Certificate
2000-09-29
2003-03-11
Bishop, Steven C. (Department: 3722)
Chucks or sockets
With fluid-pressure actuator
Radially reciprocating jaws
C279S106000, C294S086290, C294S082230, C294S106000
Reexamination Certificate
active
06530578
ABSTRACT:
FIELD OF INVENTION
The present invention relates to an arrangement for gripping and holding or releasing material, such as material held and worked in a lathe chuck, this arrangement being referred to hereinafter as a gripping arrangement.
The invention is based on a gripping arrangement that includes a piston-cylinder assembly and a number of material gripping and holding or releasing elements, so-called gripping elements and illustrated in the form of so-called gripping claws. A gripping arrangement equipped with such gripping elements can be activated by axially-related movement of said piston-cylinder assembly so as to rotate the gripping elements around a body-related axis between two positions, a first and a second position, in which the gripping-elements and gripping-claws are open and closed respectively.
Piston-cylinder assemblies of this kind include a piston-part and a cylinder-part which are adapted to move axially and reciprocatingly relative to one another through the action of a pressurized medium and a spring arrangement or spring unit.
By “piston part” is meant a piston-related arrangement where an outer peripheral surface, normally a cylindrical surface of circular cross-section, is machined to carry or present sealing means, such as packings, piston rings or the like against an inner surface of the cylinder part.
By “cylinder part” is meant a cylinder-related arrangement where an inner surface, normally a cylindrical surface of circular cross-section, that has been made smooth at least within a given area, so as to be able to co-act with the sealing means on said piston part.
Alternatively, the cylinder part may be fitted with sealing means and the piston-part made smooth, in accordance with the inventive concept.
In the case of known piston-cylinder assemblies, the cylinder-part is normally fixed in relation to a stand or frame and the piston-part is moved reciprocatingly in relation to the cylinder-part by a working medium that is pressurised in a pressure generating device.
DESCRIPTION OF THE BACKGROUND ART
Several different designs of gripping arrangements of the aforedescribed nature are known to the art.
The gripping arrangement illustrated and described in GB Patent Publication 966 644 is a particular example in this regard.
The construction taught by Patent Publication U.S. Pat. No. 2,381,657 is also relevant in this regard.
Swedish Patent Application 9200096-7 teaches a material gripping and holding or releasing arrangement which includes a piston-cylinder assembly having a number of material gripping and holding or releasing elements, so-called gripping claws.
These gripping claws are caused to pivot about a fixed shaft between two positions, an open position and a closed position, in response to axial movement of the piston-cylinder means.
In the case of these earlier known arrangements taught by the aforesaid prior publications where the gripping claws are actuated by a piston-cylinder means, the claws are moved in response to axial movement of the piston in a cylinder that is fixed in relation to a machine body.
The present invention can be considered to constitute a further development of the gripping arrangement described and illustrated in International Patent Application PCT/SE 95/01193 (having International Publication No. WO 96/12582) and reference is made to this publication for a closer understanding of the basic principles of the present invention.
SUMMARY OF THE INVENTION
Technical Problems
When taking into consideration the technical deliberations that a person skilled in this particular art must make in order to provide a solution to one or more technical problems that he/she encounters, it will be seen that on the one hand it is necessary initially to realise the measures and/or the sequence of measures that must be undertaken to this end, and on the other hand to realise which means is/are required in solving one or more of said problems. On this basis, it will be evident that the technical problems listed below are highly relevant to the development of the present invention.
When considering the present state of the art; as described above, it will be seen that a technical problem resides in providing a gripping arrangement of the aforedescribed kind that is comprised entirely of only a few individual parts, and which can be readily assembled and readily dismantled and where its component parts can be readily exchanged when becoming worn and/or when changing a gripping arrangement of one shape and size for a gripping arrangement of another shape and size.
With respect to the use of a gripping arrangement that comprises only a few individual parts, a technical problem resides in realising the significance of and the advantages afforded by using as a first part a fixed piston-part, by using as a second part a reciprocatingly movable cylinder part, by using as a third part a central body-related shaft-part, by using as a fourth part a spring unit, and by using a number of fifth parts, such as three parts, in the form of gripping elements.
Another technical problem is one of realising the significance of and the advantages associated with a gripping arrangement of the aloredescribed kind which includes a simple piston-cylinder construction in which the cylinder-part is reciprocatingly movable in relation to its longitudinal axis, said reciprocating movement also being relative to a shaft-like body-related part and also relative to said piston-part, said shaft-like part and said piston-like part both being fixed in relation to a body part.
Another technical problem is one of realising the significance of providing the cylinder-part of said piston-cylinder means with a circumferentially extending groove adapted for co-action with the gripping-element arrangement and functioning particularly as a support for the rear support surfaces of the gripping elements or gripping claws, such as the rolling surfaces thereof.
Another technical problem is one of realising the significance of and the advantages afforded by using a specially formed, body-related and shaft-like central part that will slide through the cylinder-part and which is adapted to co-act with the piston-part and firmly hold said piston-part.
It will also be seen that a technical problem is one of realising the significance of and the advantages afforded by providing the body-related part within one end-part thereof, its front part, with a number of radially extending slots or grooves adapted to respective gripping-element arrangements, and with a hole and a shaft or pin extending transversely from the centre shaft, such as to pivotally hold respective gripping-element arrangements through the medium of a hole in the gripping element.
Another technical problem is one of creating conditions with the aid of constructive means such that when the gripping arrangement is assembled, each of said transverse holes and a shaft or pin accommodated therein, and requisite stop means, such as stop screws, can be accommodated in the cylinder part.
In order to facilitate removal of the gripping-element arrangement and the replacement of one arrangement with another, it will be seen that a technical problem remains in enabling the transverse hole and a shaft located therein to take a position in which they are completely free or preferably only partially free in a position immediately adjacent said cylinder part.
It will also be seen that a technical problem resides in providing a gripping arrangement in which the retracted position of the gripping-element arrangements and an adapted immediately external position can be achieved solely by rotating the cylinder-part around the piston-part through a predetermined number of turns, such as three to four turns.
Another technical problem is one of realising the conditions required with respect to dimensioning of the depth of a groove in the cylinder-part so as to enable parts of the gripping-element arrangements to be brought to an exposed position immediately outside the cylinder-part.
Another technical problem is one of realising the significance o
Banner & Witcoff , Ltd.
Bishop Steven C.
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