GB2219542A

GB2219542A - Adjustable form tool head

Info

Publication number: GB2219542A
Application number: GB8822406A
Authority: GB
Inventors: Charles Phillip Brinlee
Original assignee: C E TOOLING Inc
Current assignee: C E TOOLING Inc
Priority date: 1988-05-17
Filing date: 1988-09-23
Publication date: 1989-12-13
Anticipated expiration: 2008-09-23
Also published as: GB2219542B; GB8822406D0

Abstract

A form tool head with an improved length adjusting mechanism is adapted to be rigidly connected with the body of a form tool or master punch holder. The head comprises a punch driver (18) which has a head (20), and a threaded shaft (24) which screws into a punch head base (12). An annular collar (26) has an angular aperture (32) engaging an angular neck (40) of the punch driver. To adjust the form tool head (10) the collar (26) is moved in a longitudinal direction against the biasing of a compression spring (28) so that holes (34) in the collar disengage locking pins (38) on the base (12) whereupon the punch driver (18) can be rotated so as to be raised or lowered relative to the punch head base (12). <IMAGE>

Description

DESCRIPTION ADJUSTABLE FORM TOOL HEAD The present invention relates to a form tool head and more particularly to a form tool head having an improved adjusting mechanism.

Form tools are used in single station or turret press machines in the sheet metal industry. These tools need to be adjusted for different forming operations and when punching sheets of different thickness. Currently, forming tools are adjusted for use in different forming operations by the tricky and time-consuming process, of loosening two set screws which normally lock an internally threaded tool head to a threaded shaft of a punch tool, turning the form tool head in a clockwise or anticlockwise direction to move the form tool head along the threaded shaft of the form tool and tightening the two set screws to hold the for tool head in place against the shaft of the forming tool.

As well as being a fiddly operation requiring the use of a screwdriver to loosen and tighten the two set screws, because the head is subjected to large forces during operation of the press machine, the two set screws may tend to work loose or the threads of the threaded shaft or head may become damaged or even stripped.

One object of the present invention is to eliminate the use of set screws on such form tool heads.

A further object is to provide an adjusting mechanism for a form tool which allows quick and accurate adjustment of the form tool to be made.

Another object of the invention to provide an adjustable form tool head which can be fitted to the body of a form tool or master punch holder.

According to the present invention a form tool head adapted for engagement with the body of a form tool comprises a punch head base adapted to be rigidly connected with the body of said form tool, a punch driver which engages with said punch head base and which is adjustable longitudinally relative to said punch head base to determine the overall length of said form tool head, length control means which engages with but is movable longitudinally relative to said punch drive and which is adapted to engage with locking means disposed on said punch head base and resilient means for holding said length control means in engagement with said locking means.

In one embodiment the form tool head has a threaded portion extending from its base so that it can be rigidly secured to the body of the form tool. The punch head base has at the end remote from the threaded portion a threaded cavity adapted to receive a threaded end of a punch driver, rotation of which results in the punch driver moving longitudinally relative to the punch head base thereby altering the overall length of the form tool head.

The length control means is slidably mounted intermediate the punch head base and punch driver.

Preferably it is in the form of an annular collar having a central aperture which is adapted to engage and grip a like shaped intermediate portion of the punch driver so that, in an adjusting position, movement of the collar in a clockwise and anticlockwise direction will result in the longitudinal displacement of the punch driver towards or away from the punch head base, thereby altering the length of the form tool head.

Preferably the collar has a plurality of spaced holes thereon which act as one half of a locking member and which half of the locking member can engage with a plurality of pins on the punch head base. When the form tool is in use, a compression spring preferably functions to hold the two locking members together.

A specific embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is a side elevation in part cross-section of an embodiment in accordance with the present invention; and Fig. 2 is an exploded view of the form tool head of Figure 1.

The form tool head 10 comprises a punch head base 12 having a threaded portion 14 for attachment to a form tool body (not shown). The punch head base 12 has a central aperture 16 which is threaded and it is through this aperture 16 that a punch driver 18 is connected.

The punch driver 18 is made of hardened steel and is of generally mushroom shaped configuration. It has a substantially convex head 20 from the underside of which extends a solid cylindrical shaft 22 the lower end 24 of which is threaded. It is the lower end 24 of this shaft 22 that engages and co-operates with the punch head base 12.

By rotating the punch driver 18 the punch driver can be made to move up or down relative to the punch head base 12.

intermediate the punch head base 12 and the punch driver 18 lies the length control means 26 and a compression spring 28. The length control means 26 is in the form of a collar comprising an annular disc 30 having an angular central aperture 32 and eight small apertures 311 equally spaced along the circumference just inside of a raised outer wall 36 which is gnurthed to aid gripping.

The collar 26 is movable longitudInally by a sliding action between a first and second position.

In a first position the collar 26 sits on the punch head base 12 such that two diametrically opposed apertures 34 of the eitht apertures sit on two diametrically opposed pins 38 formed on and projecting from the uppermost surface of the punch head base 12. In this position the angular central aperture 32 is also in contact with and grips a complementary angular portion 40 formed on the upper part of the shaft 22 of the punch driver 18, such that the punch driver 18 is prevented from turning without the collar being moved to a second position by sliding it longitudinally so that the collar is disengaged from the pins 38 of the punch head base.

in the first position a compression spring 28 holds the collar 26 down so that the diametrically opposed apertures 34 of the collar are engaged with the two pins 38 of the punch head base 12.

To adjust the form tool the collar is slid upwards to a second position so that the collar 26 disengages the punch head base 12 and is thus free to rotate. Since the angular central aperture 32 is in contact with and grips the angular section 40 of the punch driver 18 rotation of the collar 26 results in rotation of the punch driver 18 thereby moving the punch driver 18 longitudinally relative to the punch head base 12. Compression spring 28 functions by forcing the collar 26 downwards towards the base 12, so that on release of the collar 26, the collar comes back into contact with the punch head base 12 by engaging two apertures 34 in the collar 26 with the two pins 38 if the punch head base 12.Since the angular portion 40 of the punch driver 18 and the central aperture 32 of the collar 36 are also loaded together, the punch driver 18 is effectively locked in a set position to the punch head base 12.

In use, the action of the downward force exerted by the compression spring 28 prevents the collar 36 disengaging the punch head base thereby preventing any accidental disengagement.

The use of the pin and aperture locking means enables the tool to be calibrated to allow accurate, step by step adjustment to be made to the tool. Using this method adjustment by as little as 0.03mm can be made or one eighth of the pitch of the screw thread where eight apertures 34 exist on the collar 36.

The present invention should be no way limited to the embodiment described and it is to be understood that other mechanical equivalents are hereby incorporated, for example the collar could have male mating parts thereon and the base female mating parts.

Claims

1. A form tool head adapted for engagement with the body of a form tool comprises a punch head base adapted to be rigidly connected with the body of said form tool, a punch driver which engages with said punch head base and which is adjustable longitudinally relative to said punch head base to determine the overall length of said form tool head, length control means which engages with but is movable longitudinally relative to said punch drive and which is adapted to engage with locking means disposed on said punch head base and resilient means for holding said length control means in engagement with said locking means.

2. A form tool head as claimed in claim 1, wherein the punch head base has a threaded cavity and the punch driver has a threaded end adapted to engage with said threaded cavity.

3. A form tool head as claimed in the preceding claims, wherein the length control means is slidably mounted intermediate the punch head base and punch driver.

4. A form tool head as claimed in claim 3, wherein the length control means is in the form of an annular collar having a central aperture and adapted to engage with and grip a like-shaped intermediate portion of the punch driver.

5. A form tool as claimed in claim 4, wherein said annular collar comprises a plurality of spaced holes which engage with locking means composed of a plurality of pins disposed on the punch head base.

6. A form tool as claimed in claim 5 wherein said plurality of pins are composed of one or more diametrically opposed pairs of pins.

7. A form tool as claimed in any of the preceding claims wherein the resilient means is a spring.

8. A form tool as claimed in claim 12 wherein the spring is a compression spring.

9. A form tool head adapted for engagement with the body of a form tool as hereinbefore described with reference to and as illustrated in Figs. 1 and 2 of the accompanying drawings.