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Title:
LOCKING DEVICE FOR A SYMMETRIC CYLINDRICAL BODY FIXING A SEMI-FINISHED PRODUCT TO A WORKSTATION
Document Type and Number:
WIPO Patent Application WO/2018/025174
Kind Code:
A1
Abstract:
A locking device (10) for a symmetric cylindrical body fixing a semi- finished product to a workstation, comprising: - an annular locking body with movable jaws (11), which in turn comprises a base plate (12) which supports a cam mechanism (13) for moving in a radial direction a plurality of movable engagement jaws (14), - the cam mechanism (13) comprising a rotatable jaw supporting ring (15), which is adapted to be rotated by means of a threaded actuation element (16), which is screwed into a corresponding hole (17) in the base plate (12) and is designed to act on an operation tab (18) which extends from said rotatable jaw supporting ring (15), - the threaded actuation element (16) comprising a central portion (21) having a reduced cross-section which is adapted to accommodate the operation tab (18) of the jaw supporting ring (15), - the operation tab (18) being pivotable, extending from a cylindrical insert (40) that is inserted so that it can rotate within a complementarily shaped seat (41) formed in the rotatable jaw supporting ring (15).

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Inventors:
PICCOLO, Sebastiano (Via Piave 9, Camposampiero, 35012, IT)
Application Number:
IB2017/054692
Publication Date:
February 08, 2018
Filing Date:
August 01, 2017
Export Citation:
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Assignee:
REM INDUSTRIE S.R.L. (Via Cavazzana 5, Padova, 35123, IT)
International Classes:
B23B31/163; B23Q1/00
Foreign References:
EP2363225A12011-09-07
EP1952922A12008-08-06
US0406857A1889-07-09
Attorney, Agent or Firm:
MODIANO, Micaela et al. (Modiano & Partners, Via Meravigli 16, Milano, 20123, IT)
Download PDF:
Claims:
CLAIMS

1. A locking device (10) for a symmetric cylindrical body fixing a semi-finished product to a workstation, characterized in that it comprises:

- an annular locking body with movable jaws (11), which in turn comprises a base plate (12) which supports a cam mechanism (13) for moving in a radial direction a plurality of movable engagement jaws (14),

- said cam mechanism (13) comprising a rotatable jaw supporting ring (15), which is adapted to be rotated by means of a threaded actuation element (16), which is screwed into a corresponding hole (17) in said base plate (12) and is designed to act on an operation tab (18) which extends from said rotatable jaw supporting ring (15),

- said threaded actuation element (16) comprising a central portion (21) having a reduced cross- section which is adapted to accommodate the operation tab (18) of the jaw supporting ring (15),

- said operation tab (18) being pivotable, extending from a cylindrical insert (40) that is inserted so that it can rotate within a complementarily shaped seat (41) formed in the rotatable jaw supporting ring (15), and being adapted to encounter alternatively two opposite planar surfaces (42, 43) formed by corresponding shoulders of the threaded actuation element (19) which face said central portion having a reduced cross-section (21).

2. The device according to claim 1, characterized in that said pivotable operation tab (18) is provided with two opposites planar faces (45, 46).

3. The device according to one or more of the preceding claims, characterized in that said threaded actuation element (16) comprises:

- a head portion (19), which is arranged in a corresponding first internal portion (20) of said hole (17),

- said central portion having a reduced cross-section (21) adapted to accommodate the operation tab (18) of the jaw supporting ring (15),

- and a threaded tail portion (22) with a contoured recess (23) for a screwing tool, which is adapted to be screwed to a corresponding complementarily threaded second external portion (24) of said hole (17).

4. The device according to one or more of the preceding claims, characterized in that said head portion (19) of the threaded actuation element (16) is threaded and the corresponding hole portion (20) is correspondingly complementarily threaded.

5. The device according to one or more of the preceding claims, characterized in that said annular locking body (11) comprises an annular cover (25) with radial seats (26) for the jaws (14), said annular cover (25) being fixed to a corresponding annular protrusion (27) that is formed on the base plate (12).

6. The device according to one or more of the preceding claims, characterized in that said cam mechanism (13) comprises said rotatable jaw supporting ring (15), with the operation tab (18), slotted seats (29) being provided on said rotatable jaw supporting ring (15), one for each jaw (14), said slotted seats (29) extending in a tangential direction with respect to an internal perimeter (33) of the rotatable ring (15), so that a first internal end (35) of each slot (29) is proximate to the internal perimeter (33), while the opposite end (36) of said slot (29) is proximate to the external perimeter (34) of said rotatable ring (15).

7. The device according to one or more of the preceding claims, characterized in that each one of the movable jaws (14) is provided with a cylindrical operation shank (37) inserted in a corresponding slot (29).

8. The device according to one or more of the preceding claims, characterized in that said rotatable jaw supporting ring (15) is inserted in a corresponding seat (38) formed on the base plate (12), said seat being provided with a lower through opening (39) for passage and movement of the operation tab (18) in the hole (17).

Description:
LOCKING DEVICE FOR A SYMMETRIC CYLINDRICAL BODY FIXING A SEMI-FINISHED PRODUCT TO A WORKSTATION

The present invention relates to a locking device for a symmetric cylindrical body fixing a semi-finished product to a workstation.

Currently, for the reversible locking of a semi-finished product ahead of machining, such as chip-forming machining, modular support systems are known which comprise a plurality of different components designed to be combined so as to provide a stable, safe and precise support in order to keep a semi-finished product in a precise preset position available to machine tools.

Modular support systems which comprise a symmetric cylindrical body provided at one end with a centering collar and in a central region with a perimetric recess that forms an engagement undercut for a corresponding locking device are currently known and increasingly widespread owing to their practicality and functionality.

This locking device generally comprises an annular locking body with movable jaws, which in turn comprises a base plate that supports a cam mechanism for the movement in a radial direction of a plurality of movable engagement jaws, said cam mechanism comprising a rotatable jaw supporting ring, which is adapted to be rotated by means of a threaded actuation element, which is screwed into a corresponding hole in said base plate, designed to act on an operation tab that extends from said rotatable jaw supporting ring.

Said threaded element comprises:

- a threaded head portion, which is arranged in a corresponding first internal complementarily threaded portion of said hole,

- a central portion having a reduced cross-section and adapted to accommodate the operation tab of the jaw supporting ring,

- and a threaded tail portion, with a contoured recess for a screwing tool, which is adapted to be screwed to a corresponding second external complementarily threaded portion of said hole.

By rotating the threaded actuation element, the rotation of the jaw supporting ring is achieved which, by virtue of the cam mechanism, causes the advancement or retraction in a radial direction of the jaws, which enter or exit from the perimetric engagement recess of the symmetric cylindrical body to which a semi-finished product is fixed.

In various locking and testing trials, known locking devices reveal limitations and criticalities which might lead to malfunctions, failures, or at least to less than optimum operation of the system.

An important problem is the operation tab that extends from the rotatable jaw supporting ring, being monolithic therewith.

Said operation tab is cylindrical and is adapted to encounter alternatively two opposite planar surfaces formed by corresponding shoulders which face the central portion having a reduced cross- section of the threaded operation element.

Continuous mutual pressure with point-like contact between the external cylindrical surface of said operation tab and the planar surfaces of the actuation element entail a problem of upsetting of said contact surfaces.

A deformation of said contact surfaces can produce an irregular rotary motion of the rotatable jaw supporting ring, with consequent risk of less- than-perfect closure of the locking device.

The aim of the present invention is to provide a locking device for a symmetric cylindrical body fixing a semi-finished product to a workstation that is capable of obviating the limitations of similar known devices.

Within this aim, an object of the invention is to provide a device that ensures a regular rotary motion of the jaw supporting ring and a consequent continuous and repeatable tightening of the locking device.

Another object of the invention is to provide a device that in any case has a performance, effectiveness and durability that are not lower than similar devices of the known type. This aim, as well as these and other objects which will become better apparent hereinafter, are achieved by a locking device for a symmetric cylindrical body fixing a semi-finished product to a workstation according to claim 1.

Further characteristics and advantages of the invention will become better apparent from the description of a preferred but not exclusive embodiment of the locking device according to the invention, illustrated by way of non-limiting example in the accompanying drawings, wherein:

Figure 1 is a perspective cutout view of a device according to the invention;

Figure 2 is a perspective view of a detail of Figure 1 ;

Figure 3 is a perspective view of a detail of the invention;

Figure 4 is an exploded perspective view of the device according to the invention.

With reference to the figures, a locking device for a symmetric cylindrical body fixing a semi-finished product to a workstation is designated generally by the reference numeral 10.

The locking device 10 comprises:

- an annular locking body with movable jaws 11 , which in turn comprises a base plate 12 supporting a cam mechanism 13 for moving in a radial direction a plurality of movable engagement jaws 14,

- the cam mechanism 13 comprises a rotatable jaw supporting ring

15, which is adapted to be rotated by means of a threaded actuation element

16, which is screwed into a corresponding hole 17 in the base plate 12 and is designed to act on an operation tab 18 which extends from the rotatable jaw supporting ring 15,

- the threaded actuation element 16 comprising:

- a head portion 19, arranged in a corresponding first internal portion 20 of the hole 17,

- a central portion 21 having a reduced cross-section which is adapted to accommodate the operation tab 18 of the jaw supporting ring 15,

- and a threaded tail portion 22, with a contoured recess for a screwing tool, which is adapted to be screwed to a corresponding complementarily threaded second external portion 24 of the hole 17.

It should be understood that the head portion 19 of the threaded actuation element 16 can be threaded and the corresponding hole portion 20 can be correspondingly threaded complementarity or can be cylindrical with a smooth surface.

The operation tab 18 is pivotable, extending from a cylindrical insert 40 which is inserted rotatably in a complementarily shaped seat 41 formed on the rotatable jaw supporting ring 15.

Said tab is adapted to encounter alternatively two opposite planar surfaces 42 and 43 which are formed by corresponding shoulders which face the central portion 21 having a reduced cross-section of the threaded actuation element 16.

In particular, in the present constructive example, the operation tab 18 is provided with two opposite planar faces 45 and 46.

By virtue of these planar faces 45 and 46 and the operation tab 18, which is pivotable by virtue of the cylindrical insert 40, the contact between the planar surfaces 42 and 43 of the actuation element 16 is no longer point- shaped and the thrust or traction force is better distributed with constancy at all the allowed rotation angles of the rotatable ring 15, with consequent elimination of the risk of upsetting the contact surfaces.

In Figure 1 , the locking device 10 is shown in the active configuration with a symmetric cylindrical part supporting body 30 inside it and with the movable jaws 14 inserted in an external perimetric engagement recess 31 thereof.

The part supporting body 30 is shown fixed to a generic semi-finished product 32.

In particular, in the present exemplary embodiment of the invention, the annular locking body 11 comprises an annular cover 25 with radial seats 26 for the jaws 14; the annular cover 25 is fixed to a corresponding annular protrusion 27, which is formed on the base plate 12 by means of a series of screws 28.

The cam mechanism 13 comprises the rotatable jaw supporting ring

15, with the operation tab 18, slotted seats 29 being provided on the rotatable jaw supporting ring 15, one for each jaw 14; said slotted seats 29 extend in a tangential direction with respect to an internal perimeter 33 of the rotatable ring 15, so that a first internal end 35 of each slot 29 is proximate to the internal perimeter 33, while the opposite end 36 of the same slot 29 is proximate to the external perimeter 34 of the rotatable ring 15.

Each one of the movable jaws 14 is provided with a cylindrical operation shank 37 which is inserted in a corresponding slot 29.

The rotatable jaw supporting ring 15 is inserted in a corresponding seat 38 that is formed on the base plate 12, said seat having a lower through opening 39 for the passage and movement of the operation tab 18 in the hole 17, available to the threaded actuation element 16.

The rotation of the rotatable jaw supporting ring 15, determined by the screwing or unscrewing of the threaded actuation element 16, entails the redirection of the cylindrical shanks 37 in the slots 29 from a more inward radial position to a more outward radial position or vice versa, the movement of the cylindrical shanks 37 causing the consequent radial movement of the associated movable jaws 14 within the radial seats 26 formed in the annular cover 25.

In practice it has been found that the invention achieves the intended aim and objects.

In particular, the invention provides a device that ensures regular rotary motion of the jaw supporting ring and a consequent continuous and repeatable tightening of the locking device, by virtue of the particular pivotable operation tab which is appropriately shaped for better force distribution.

Moreover, the invention provides a device that in any case has a performance, effectiveness and durability which are not lower than similar devices of the known type.

The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims; all the details may further be replaced with other technically equivalent elements.

In practice, the components and materials used, so long as they are compatible with the specific use, as well as the contingent shapes and dimensions, may be any according to the requirements and the state of the art.

The disclosures in Italian Utility Model Application no. 202016000081443 (UA2016U164687), from which this application claims priority, are incorporated herein by reference.

Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.