GB2292535A - Workpiece holding and aligning assembly - Google Patents

Abstract

Apparatus 10 for aligning a stack of sheet material with a housed guillotine tool, comprising a tool assembly 22, 24 arranged to be attached to a press (10, Fig. 2), a demountable workpiece holder assembly arranged to hold a stack of papers, and means to releasably align and lock the tool assembly with respect to the workpiece holder assembly. The tool assembly is housed in a cabinet 29 in order to maintain a safe cutting zone. The workpiece holder comprises a bed 44 with a mat 56 on which a stack of sheet material 52 is placed. An alignment guide 32 is placed on top of the stack and a magnetic locking means 36 at the end of the guide is aligned with a line to be cut. Clamp 38 secures the stack firmly to the bed. The workpiece holder is placed on the apparatus using grip 40 until guide wall 34 abuts a knife 22 and is locked to it by means of the magnet. <IMAGE>

Description

Safe Handling And Precise Self-aligning Assemblies This invention relates to a method for precise alignment of a workpiece to a tool, yet maintaining a safe distance from the potentially hazardous tool.

The invention was conceived due to recognition of these problems: (i) A need for affordable table-top and powered guillotine cutter: Hydraulic or electric powered guillotine machines are typically big and heavy, and suited for off-set printing firms located in industrial areas. For retail shops, where space is a premium, there is no suitable desktop type of powered cutting equipment. Therefore many shop owners, such as the l-hour photo-labs, have to purchase hand-operated cutting device that cuts loose sheets of photopapers, usually one at a time.

(ii) Punching operations are typically unsafe and ahgnment-dzfficult: Operators knew that the cutting, punching, or stamping of a workpiece, is an inherently time consuming trial-and-error process. Besides, the operation of making precise positioning relative to the tool has exposed an operator to a tool's potential hazard due to close proximity adjustments.

(iii) Availability of low-cost general purpose press equipment: In the market, there are many low cost general purpose press, punching or shearing equipment as well as simple, heavy duty clamp devices. All these general purpose equipment are meant to undertake various size workpieces that do not require precision positioning nor quick operational speed.

(iv) Public safety or environmentally exclusive considerations: Almost all industrial press equipment are handled by experienced operators.

Costly or sophisticated measures are undertaken to ensure safe operation. Industrial accidents still occur, such as during the use of guillotine or hot stamping presses.

In some cases, cost is escalated due to the need for environmentally exclusive operation, for example, a clean air housing maybe needed for the tool-to-workpiece activity.

Additionally, if an equipment is to be operated in a retail outlet, whereby separate work-space or restricting public's exposure to a tool is difficult to implement, than an improved means of safe guarding the public is necessary.

The seemingly unrelated variables, as stated in the preceding paragraphs, forms the challenge for this invention. An inventive solution would allows a press equipment, or a simple clamping device, to perform functions similar to a factory pre-built precision equipment at a high safety level of operation.

In an automated environment, to minimize the cost of re-tooling to accommodate different workpiece sizes, the novel solution has another advantage of allowing a fixed tool to continue performing its activity on every in-coming workpiece, irrespective of the various sizes.

According to the present invention, there is provided a cutting jig comprising a knife assembly arranged to be demountably attached to a punch, a workpiece holder assembly arranged to hold a workpiece, such as a stack of paper, in a predetermined position, and means for aligning the knife assembly with respect to the workpiece holder assembly.

The means for aligning and abutting the two assemblies may comprise a magnet mounted on the holder assembly and positioned to draw the knife of the knife assembly into an abutting relationship with an opposing surface of the holder assembly.

With the means available for self-alignment of the two assemblies. without a need for operator's close proximity supervision, the knife assembly can be kept from anybody's reach by a simple cabinet casing. Visible view of the equipment's operation can be maintained by using transparent casing material. In this instance, the workpiece holder assembly becomes a drawer block that slides into a tool assembly cabinet. Additionally, the novelty of these assemblies allows the prealignment of a tool-to-workpiece positioning, at a distance from the tool.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the invention, preferred for its low built-up cost and designing simplicity, will now be described by way of a paper-cutting guillotine example with reference to the accompanying drawings.

Description of materials used: Press machine 10 comprising press-table 12, piston 14.

Tool assembly 20, comprising the metal knife 22 (knife serves as the alignment guide and as a cutting tool), press-tool attachment 24, swivel-door 26, cabinet housing 29.

Workpiece holder assembly 30, comprising the aluminium alignment guide 32, guide wall 34, permanent magnet-lock 36, workpiece & guide clamp 38, aluminium sliding drawer grip 40, assembly end-wall 42, aluminium assembly bed 44.

The stack of paper as the workpiece 52, line of cut 54, and a replaceable elastic mat 56. The primary purpose of the elastic mat base is to absorb the knife's impact so as to minimize damaging the razor-sharp edge of the knife.

Description of use: First, the precision made press-tool attachment 24 is properly attached to a press movable piston. The knife 22 is inserted into the press-tool attachment 24 and checked for alignment before securing. The transparent cabinet housing 29, less the removable swivel-door 26, is placed around the tool assembly 20 and secured to the press table 12. Thereafter, the swivel-door 26 is affixed onto the cabinet housing 29 by a simple pivot joint method whereby both top ends of the door have cylindrical pins for slotting into two pre-drilled holes on the walls of the housing 29.

An emptied workpiece holder assembly 30 is placed on any work-table, at a safe distance from the tool assembly 20. A stack of paper 52 is placed on top of the elastic mat 56 in the workpiece assembly 30. Upon the guide-wall 34 being visually seen to be aligned with the line of cut 54, the alignment guide 32 is secured by tightening clamp 38. The line of cut 54, located at the top of the paper, could be a pre-marked line at the top piece of paper.

After the workpiece 52 is properly secured to the assembly 30 by the action of the clamp 38 onto the guide 32, the whole assembly 30 is placed on the press table 12 and then slide-push past the swivel-door 26, towards the knife 22 inside the cabinet housing 29. Due to the magnetic pull from the magnet-lock 36, the guidewall 34 abuts on the knife 22 and stays locked as shown in Figure 1.

Figure 2 shows the knife 22 downward stroke motion while the two assemblies (20, 30) remain locked. Additionally, Figure 2 shows the transparent cabinet 29, including a swivel door 26, for housing the knife assembly. The cutting job is completed when the tool assembly returns to its original position. The operator pulls out the workpiece holder assembly 30 for the removal of the workpiece.

It should be understood that many modifications and adaptations of the invention will become apparent to those skilled in the art and it is intended to encompass such obvious modifications and changes in the scope of the claims appended. Some examples of the adaptations to the invention: a) Additional door-safety mechanism can be added to pre-locked the swiveldoor 26 such that it is free to swing only when the one portion of the assembly bed 44 is first inserted past-behind the swivel door, through a swivel door-to-press table gap, to activate a spring door-lock release mechanism.

b) The workpiece movement towards the tool assembly can be assisted by gravity force via slanting the press table 12 at an appropriate angle. The tool's relationship has to be maintained such as having the tool assembly 20 being slanted at a similar angle to the press table 12.

c) Permanent magnet 36 being replaced by electromagnets. The electromagnets can be controlled to attract or repel the workpiece holder assembly.

d) The matchingly opposed profiles of the two alignment guides can be in different forms such as the use of precision guide-rails, either located on the press table or attached to the housing, to enhance workpiece accurate movement towards the tool assembly. In this case, the alignment guides are at a certain distance away from the tool activity.

f) Knife 22 can be replaced with any other tool or devices to perform other type of activities such as hot-stamping or silk-screen printing.

g) Additional screw-adjustable mechanism can be provided, if necessary, such that the length of cut on the workpiece 52 is easily determined by adjusting the distance of the guide-wall 34 from a fixed workpiece assembly end-wall 42.

Claims (11)

1. A system for engaging an active tool into a precise position relative to a workpiece, comprising a housed tool assembly arranged to be demountably attached to a press, a demountable workpiece holder assembly arranged to hold a workpiece, in a predetermined position, and a releasable means to forcibly align and lock the tool assembly with respect to the workpiece holder assembly.

2. A system as in claim 1 wherein the means to align and lock comprise a male alignment guide, integral to the tool assembly, and another matchingly opposed alignment guide, integral to the workpiece holder assembly.

3. A system as in claim 2 wherein the means to align comprise one alignment guide with a flat surface, and the other alignment guide comprise an identical flat surface.

4. A system as in claim 2 wherein the alignment guide, integral to the workpiece holder assembly, when secured to the workpiece, allows visual inspection of the would-be tool position relative to the workpiece.

5. A system as in claim I or claim 2 wherein the means to forcibly align comprise one assembly being positioned to draw the other assembly into an abutting relationship.

6. A system as in any preceding claim wherein the means to forcibly align comprise an attractive force of a magnetic device on at least one alignment guide and the other alignment guide comprise a magnetic material composition.

7. A system as in claim I or claim 2 wherein the releasable means to lock, comprise a lock on one alignment guide and a lock receptor on the other alignment guide.

8. A means to lock as in claim 1 wherein the lock comprise the use of at least one magnetic device mounted on an alignment guide.

9. A system as in any preceding claim wherein the housed tool assembly comprised an exclusive operational zone achieved by having the tool assembly being enclosed in a cabinet box with at least one suspended swivel-door, the workpiece holder assembly being built as a drawer block.

10. A system as in claim 1 wherein the active tool comprise a cutting knife, which co-operates with the magnetic device mounted on the workpiece holder assembly, concurrently facilitating its surface as the alignment plane for the two assemblies.

11. A system substantially as described herein with reference to Figure 1 and Figure 2 of the accompanying drawings.