GB2164885A - Marking machine - Google Patents

Abstract

A marking machine of the kind in which a workpiece is indented with the required mark by means of a die (shown in broken lines), the die being of arcuate or cylindrical form and the operation of marking a workpiece involving two successive movements, a first movement to bring the periphery of the die into engagement with the workpiece and a second movement, being a rotational movement of the die, to bring about the required marking as the die and workpiece move together in engagement. So that the speed of operation can be increased and operator fatigue reduced, both movements are brought about by a single manually operable lever 32 and during successive arcs of movement constituting a single operative stroke of said lever. Preferably a lowering cam 28 is mounted on the shaft 16 of lever 32 which shaft also carries the die. <IMAGE>

Description

SPECIFICATION Marking machine The invention relates to a marking machine of the kind in which a workpiece is indented with the required mark by means of a die, and more particularly to a marking machine of this kind in which the die is of arcuate or cylindrical form and the operation of marking a workpiece involves two successive movements, that is to say a first movement to bring the periphery of the die into engagement with the workpiece and a second movement, being a rotational movement of the die, to bring about the required marking as the die and workpiece move together in engagement.

In one particular machine of the kind referred to the two successive movements are brought about by two successive movements on the part of the operator, that is to say by the operation of a foot pedal to bring the periphery of the die into engagement with the workpiece and by the operation of a manually operable lever to rotate the die. However, it has been realised that the operation of such a machine in this fashion has a number of drawbacks. It is physically tiring for the operative and relies entirely on his skill and dexterity to perform the two successive functions required of him in rapid sequence without error. A requirement to perform two successive functions in this manner inevitably tends to slow the speed of production, especiaily as the operator becomes physically fatigued.The object of the invention is to provide a marking machine in which the drawbacks referred to will be at least alleviated.

According to the invention, there is provided a marking machine of the kind referred to and in which a first movement to bring the periphery of the die into engagement with the workpiece, and a second movement to bring about the required marking as the die and workpiece move together in engagement, are both brought about by a single manually operable lever. Preferably, the first and second movements will be brought about during successive arcs of movement constituting a single operative stroke of the manually operable lever. Preferably, also, the first movement will be brought about by cam and follower means, the latter preferably being associated with resilient means such that, when the periphery of the die has been brought into engagement with the workpiece said resilient means are caused to yield.In this case, screw means will preferably be provided for pre-loading the resilient means to a pre-determined extent. The resilient means may be constituted by a stack of "Belleville" spring washers.

The cam of the cam and follower means, and the die, will preferably be mounted on a horizontally disposed shaft, the latter preferably being rotatably mounted in a block connected to a housing which is slidably adjustable along a vertical column, the block either being slidably mounted for movement relative to said housing or being pivotally connected about a horizontal axis to said housing for vertical movement of the shaft carrying the die. Screw means will preferably be provided for vertically adjusting the housing up or down the vertical column. A baseplate from which the column is vertically upstanding will preferably be capable of being fitted with different mountings to suit various types of workpiece which are to be marked.

In order that the invention may be fully understood and readily carried into effect, the same will now be described, by way of example only, with reference to the accompanying drawings, of which: Figure 1 is a side view of a marking machine embodying the invention, Figure 2 is a sectional view on the line 2-2 in Figure 1, and Figure 3 is a sectional view on the line 3-3 in Figure 2.

Referring now to the drawings, the marking machine there illustrated is a bench type machine and includes a baseplate 10 from which a substantial column 12 is vertically upstanding. The baseplate is capable of being fitted with different mountings (not shown) to suit various types of workpiece which are to be marked, that is to say solid cylindrical, hollow cylindrical or flat. Overlying the baseplate is a housing, generally indicated 14, which is adjustably mounted on the vertical column.

Mounted on a horizontal shaft 16 located beneath the housing is a cylindrical die (shown in chain-dotted lines) which is capable of marking the workpiece with a required marking standing proud of the surface of the die. The marking operation thus requires two successive movements, that is to say a first movement to bring the periphery of the die into engagement with the workpiece and a second movement, being a rotational movement of the die, to bring about the required marking as the die and workpiece move together in engagement.

Referring in particular to Figure 1, it will be seen that the housing generally indicated 14 is a two-part housing, comprising a main body 18 capable of being clamped at an adjusted height on the column (a screw 13 and manually operable handle 15 being down the vertical column), and a secondary body part 20 in this case pivotally connected to said main body by means of a cross shaft 22. A tension spring 24 is provided for urging a forward portion of the secondary body part upwardly towards the main body.

The horizontal shaft 16 on which the cylindrical marking die is mounted is provided with a flange 17 against which the die is clamped, the flange having a pair of projecting pins 19 for drivably engaging the die. A bush 21 and a clamping washer 23 are acted upon by a screw 25 to clamp the die in driving engagement with the flange 17 (but of course it will be obvious that the bush and clamping washer could be formed integrally together and it will probably be preferred to form them integrally together). The shaft 16 is located in bearings 26,26 in the secondary body part 20. The position of the forward portion of the secondary body part in relation to the main body is determined by a cam 28 which is secured on the cross shaft 22 by a pin 30. An end of the horizontal shaft 16 remote from the marking die is provided with a manually operable lever 32.Consequently, with the main body of the housing 14 appropriately positioned on the vertical column, and from an initial starting point with the periphery of the marking die spaced from the surface of the workpiece to be marked, the first movement to bring the periphery of the die into engagement with the workpiece comprises a first arc of movement of the manually operable lever from an "AT REST" position.

Referring now in particular to Figure 2, resilient means generally indicated 38 are located in the main body of the housing 14, said resilient means being constituted by a stack of "Belleville" spring washers 40 housed within a cylindrical sleeve 42 located in said main body by means of a circlip 44. The stack of spring washers can be pre-loaded to an adjustable extent by means of a knurled cap 46 which has screwthreaded engagement with the upper end of the sleeve as shown. A guide pin 41 on which the "Belleville" spring washers are located extends upwards through a clearance hole in the cap 46. The lower end of the stack of spring washers acts downwards against a carrier 48 for a roller 50 which acts against the periphery of the cam 28, the roller being rotatably mounted on a pin 51.An upper end of the carrier 48 is provided with a collar 52 which can bear against a shoulder formed within the cylindrical sleeve. Normally, that is to say when the manually operable lever is in its "AT REST" position in which it is shown in the drawings, the collar 52 formed on the roller carrier abuts against said shoulder. However, when the lever 32 is moved through its first arc of movement to bring the periphery of the die into engagement with the workpiece, the roller carrier is lifted away from the shoulder within the cylindrical sleeve by the cam acting against the roller and, consequently, the pressure which is applied to the surface of the workpiece by the marking die and the extent by which the workpiece is indented with the required mark is determined by the load which the stack of "Belleville" spring washers apply against the roller carrier.

The rotational movement of the die to bring about the required marking of the workpiece as the die and workpiece move together in engagement with pre-determined load is effected by a further arc of movement of the manually operable lever. If the workpiece is of cylindrical shape, the rotation of the die will cause a contra-rotation of the workpiece. If the workpiece is flat, it will be mounted so that it is moved linearly by the rotation of the die. The extent of die rotation is limited by an angularly adjustable stop lever 34 which abuts against a stop peg 36.

It has been found that the machine described above has completely overcome the drawbacks previously referred to in the prior art. The fact that the two successive movements referred to are broughtabout in sequence during a single operative stroke of the manually operable lever has resulted in an increased rate of production capability and in reduced operator fatigue. It is found that since the resilient means are constituted by a stack of "Belleville" spring washers, the characteristics of these washers enable the workpieces to vary very slightly in size without affecting to any substantial extent the quality of the marking applied. This is because a stack of "Belleville" spring washers permit a relatively large movement with a more or less constant pressure.

Various modifications may be made. For example, it is not essential for the resilient means to be constituted by a stack of "Belleville" spring washers, and indeed it is pos sible that such means could be arranged to yield under tension rather than under compression. The cap 46 for adjusting the force of the resilient means need not necessarily be knurled, and may indeed be easier to turn if fitted with a tommy bar or drilled for the removable connection of a tommy bar. Furthermore, it is not essential for the first movement, to bring the periphery of the die into engagement with the workpiece, to be brought about by cam and follower means. It could be brought about by a suitable linkage arrangement, lost motion means being provided to permit the second movement to take place, to bring about the required marking as the die and workpiece move together in engagement, when said linkage arrangement has brought about the required first movement.

The block need not necessarily be pivotally connected to the housing; it could be slidably mounted for movement relative to the housing.

Claims (9)

1. A marking machine of the kind in which a workpiece is indented with the required mark by means of a die, the die being of arcuate or cylindrical form and the operation of marking a workpiece involving two successive movements, that is to say a first movement to bring the periphery of the die into engagement with the workpiece and a second movement, being a rotational movement of the die, to bring about the required marking as the die and workpiece move together in engagement, in which a first movement to bring the periphery of the die into engagement with the workpiece, and a second movement to bring about thy required marking as the die and workpiece move together in engagement, are both brought about by a single manually operable lever.

2. A marking machine according to claim 1, in which the first and second movements are brought about during successive arcs of movement constituting a single operative stroke of the manually operable lever.

3. A marking machine according to either one of the preceding claims, in which the first movement is brought about by cam and follower means, the latter being associated with resilient means such that, when the periphery of the die is brought into engagement with the workpiece said resilient means are compressed.

4. A marking machine according to claim 3, in which screw means are provided for preloading the resilient means to a pre-determined extent.

5. A marking machine according to either one of claims 3 and 4, in which the resilient means are constituted by a stack of "Belleville" spring washers.

6. A marking machine according to any one of the preceding claims, in which the cam of the cam and follower means, and the die, are mounted on a horizontally disposed shaft, the latter being rotatably mounted in a block connected to a housing which is slidably adjusted along a vertical column, the block either being slidably mounted for movement relative to said housing or being pivotally connected about a horizontal axis to said housing for vertical movement of the shaft carrying the die.

7. A marking machine according to claim 6, in which screw means are provided for vertically adjusting the housing up or down the vertical column.

8. A marking machine according to either one of claims 6 and 7, in which a baseplate from which the column is vertically upstanding is capable of being fitted with different mountings to suit various types of workpiece which are to be marked.

9. A marking machine constructed, arranged and adapted to operate substantially as hereinbefore described with reference to and as illustrated by the accompanying drawings.