GB1602631A

GB1602631A - Key cutting machines

Info

Publication number: GB1602631A
Application number: GB122678A
Authority: GB
Original assignee: ATKINSON ENG CO LEEDS Ltd
Current assignee: ATKINSON ENG CO LEEDS Ltd
Priority date: 1978-05-26
Filing date: 1978-05-26
Publication date: 1981-11-11

Description

(54) IMPROVEMENTS IN AND RELATING TO KEY CUTTING MACHINES (71) We, ATKINSON ENGIN EERING COMPANY (LEEDS) LIMITED, a British Company of Farnley Low Mills, Whitehall Road, Leeds 12, do hereby declare the invention for which we pray that a patent may be granted to us and the method by which it is to be performed, to be particularly described in and by the following statement:- The invention relates to key cutting machines.

Key cutting machines are known comprising a key holder and a probe movable relative to one another, the relative movement being generally in the length direction of a sample key having a profiled operative lengthwise edge held in said holder in use of the machine with the probe following the profile of the operative edge of the key, and the machine further comprising rotary cutting means operatively associated with means providing said relative movement for cutting a key blank to a profile similar to that of the sample key.

Such a machine will be referred to hereinafter in the specification as a key cutting machine of the type aforesaid. A disadvantage of key cutting machines of the type aforesaid as hitherto produced lies in the fact that great care needs to be taken by the operator of the machine when bringing the probe and key together at one end of the operative edge to avoid damage to the cutter or key blank and to ensure accurate copying of the profile of the sample key, and the object of the invention is to enable machines to be used with a minimum of skill and attention by the operator whilst yet avoiding the above-mentioned damage and inaccuracy.

According to the invention there is provided a cutting machine of the type aforesaid comprising means for moving the probe and key holder from start positions automatically towards one another transversely of the length of a sample key held, in use of the machine, in said holder the path of said movement being in an arc about an axis parallel both to the plane of said key and to the rotary axis of the cutting means.

Preferably said means is adapted to cause subsequent automatic relative movement between the probe and the key holder successively (a) generally in the said direction, (b) away from one another transversely of said direction and (c) in a direction opposite to that referred to at (a).

Preferably said means comprises an electric motor connectible to a source of electric energy through a switch, and means to move the switch to an off position when the probe and key holder are returned to their start position. The relative movement of the probe and key holder in the said direction, and transversely of said direction and the movement of the said switch are preferably each controlled by cam and follower means.

An embodiment of the invention will now be described by way of example and with reference to the accompanying drawings of which: Figure 1 shows diagrammatically a portion of one embodiment of the invention in an elevation; and Figure 2 shows the same portion in side elevation.

A frame, not shown in the drawing, supports a shaft 4 by which a bar 2 is capable of rotating about an axis 5 and along which it is capable of sliding. The frame also rigidly supports a probe 30, and pivots for a cutting wheel 32, a cam 20 and a lever 36. A pair of arms 6 and 8 extend radially from the bar 2 with respect to the axis 5 of shaft 4. The arms terminate in clamps 10 secured by thumb screws 12 for securing a sample key 14 and a key blank 16 to the radial arms 6 and 8 respectively.

The key and the blank are thereby secured in a plane approximately tangential to the cylinder centred on the axis 5. The arms 6 and 8 are so long that for slight angular movement of the bar 2 about the shaft 4, the arcuate movement of the key and blank approximate to rectilinear movement.

As shown in detail only in Figure 1 cam 20, rotating in the direction shown by arrow 22 about axis 24 is adapted to displace plunger body 26 to the left in the figure so as to tilt bar 2 in a clockwise direction against means (not shown) which tend to urge the bar and radial arms to the position shown in dotted line.

As shown in full lines the bar 2 and the radial arms 6 and 8 have been tilted to such an extent that the key 14 and the key blank 16 have respectively made contact with the probe 30 and cutting wheel 32. The probe 30 is of such dimensions as to be capable of following the profile of the sample key precisely and the arrangement of clamps 10, the probe 30 and the cutting wheel 32 is such that as the probe follows the profile of key 14 the wheel 32 cuts a similar profile in key blank 16. In order that the probe 30 shall enter fully into the indentations of the key 14, the plunger body 26 is formed as a cylinder accommodating a spring 27 which urges piston 28 outwardly to abut against the bar 2. In urging the piston 28 outwardly, the spring 27 must overcome the force previously referred to as tending to rotate the bar 2 about the shaft 4 in an anticlockwise direction.The relative movement of piston 28 in plunger body 26 is limited by the length of slot 29 in plunger body 26 which accommodates pin 23 projecting from piston 28.

In a complete key cutting cycle the cam 20 makes one complete revolution which terminates in the plunger body 26 moving to the right in the figure and consequently the radial arms 6 and 8 rising to the position shown in dotted lines in Figure 1. During the cycle the bar 2 is traversed along the shaft 4 in the direction shown by arrow 34 by means of lever 36 actuated by a further cam not shown. The extent of traverse of bar 2 along shaft 4 corresponds to the length of the indented operative edge of the key 14.

The end of the traverse coincides with the raising of the radial arms 6 and 8 and the traverse cam subsequently allows the bar 2 to slide back to the original position under a conventionally applied force not shown.

A further cam and follower arrangement are provided so that on the return of the bar 2 to its original lateral position with the arms 6 and 8 tilted upwardly the drive to the cams and to the cutting wheel 32 is switched off.

A start switch is provided which overrides the above mentioned cam operated switch.

For cutting a key the following sequence is adopted. With the machine in its start position, that is to say with the radial arms 6 and 8 raised to the position shown in dotted lines in Figure 1 and with the bar 2 to the right in Figure 2, a sample key and a key blank are clamped in pre-determined positions by clamps 10 and the start switch is operated. Cutting wheel 32 begins to rotate and cam 20 is turned to lower arms 6 and 8 until the key 14 makes contact with probe 30 at one end of the indented operative edge thereof. Simultaneously the key blank 16 is lowered against the cutting wheel 32 and the blank is cut to a depth corresponding to that of the sample key. Lever 36 then begins to cause bar 2 to traverse to the left in Figure 2 and as the probe 30 follows the profile of the key 14 so the cutting wheel 32 cuts a similar profile in the blank 16.At the end of the traverse the cam 20 allows the arms 6 and 8 to rise and the traverse cam allows bar 2 to slide to the right in Figure 2 and the cam operated switch switches off the machine.

The sample key and the newly cut key are removed from the clamps 10 and the machine is ready for a further operation. It will be appreciated that the machine can be operated with relatively unskilled labour and can be left unattended once a key and blank have been clamped in correct position and the start switch operated. The pressure of the key blank against the cutting wheel 32 is controlled by the parameters of the system which can be arranged to avoid overloading of the cutting wheel. The stopping of the cutting wheel at the end of the cycle is an added safety factor.

WHAT WE CLAIM IS: 1. A key cutting machine of the type aforesaid comprising power means for moving the probe and key holder from spaced apart start positions towards one another transversely to the length of a key held, in use of the machine, in said holder the path of said movement being in an arc about an axis parallel both to the plane of said key and to the rotary axis of the cutting means.

2. A key cutting machine as claimed in Claim í wherein said power means effect, subsequent to said movement, further relative movement between the probe and the key holder automatically and successively (a) in one direction of the length of the key in use, (b) away from one another transversely of said direction and (c) in the direction opposite to that referred to in (a).

3. A key cutting machine, according to Claim 2 adapted relatively to move the probe and key holder automatically in a complete cycle.

4. A key cutting machine according to Claim 3 wherein said power means comprises an electric motor connectible to a source of electric energy through a switch, and means to move said switch to an off position at a predetermined relative position of probe and key holder.

5. A key cutting machine according to Claim 2, Claim 3 or Claim 4 comprising cam

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

As shown in detail only in Figure 1 cam 20, rotating in the direction shown by arrow 22 about axis 24 is adapted to displace plunger body 26 to the left in the figure so as to tilt bar 2 in a clockwise direction against means (not shown) which tend to urge the bar and radial arms to the position shown in dotted line.

As shown in full lines the bar 2 and the radial arms 6 and 8 have been tilted to such an extent that the key 14 and the key blank 16 have respectively made contact with the probe 30 and cutting wheel 32. The probe 30 is of such dimensions as to be capable of following the profile of the sample key precisely and the arrangement of clamps 10, the probe 30 and the cutting wheel 32 is such that as the probe follows the profile of key 14 the wheel 32 cuts a similar profile in key blank 16. In order that the probe 30 shall enter fully into the indentations of the key 14, the plunger body 26 is formed as a cylinder accommodating a spring 27 which urges piston 28 outwardly to abut against the bar 2. In urging the piston 28 outwardly, the spring 27 must overcome the force previously referred to as tending to rotate the bar 2 about the shaft 4 in an anticlockwise direction.The relative movement of piston 28 in plunger body 26 is limited by the length of slot 29 in plunger body 26 which accommodates pin 23 projecting from piston 28.

In a complete key cutting cycle the cam

20 makes one complete revolution which terminates in the plunger body 26 moving to the right in the figure and consequently the radial arms 6 and 8 rising to the position shown in dotted lines in Figure 1. During the cycle the bar 2 is traversed along the shaft 4 in the direction shown by arrow 34 by means of lever 36 actuated by a further cam not shown. The extent of traverse of bar 2 along shaft 4 corresponds to the length of the indented operative edge of the key 14.

The end of the traverse coincides with the raising of the radial arms 6 and 8 and the traverse cam subsequently allows the bar 2 to slide back to the original position under a conventionally applied force not shown.

A further cam and follower arrangement are provided so that on the return of the bar

2 to its original lateral position with the arms 6 and 8 tilted upwardly the drive to the cams and to the cutting wheel 32 is switched off.

A start switch is provided which overrides the above mentioned cam operated switch.

For cutting a key the following sequence is adopted. With the machine in its start position, that is to say with the radial arms 6 and 8 raised to the position shown in dotted lines in Figure 1 and with the bar 2 to the right in Figure 2, a sample key and a key blank are clamped in pre-determined positions by clamps 10 and the start switch is operated. Cutting wheel 32 begins to rotate and cam 20 is turned to lower arms 6 and 8 until the key 14 makes contact with probe 30 at one end of the indented operative edge thereof. Simultaneously the key blank 16 is lowered against the cutting wheel 32 and the blank is cut to a depth corresponding to that of the sample key. Lever 36 then begins to cause bar 2 to traverse to the left in Figure 2 and as the probe 30 follows the profile of the key 14 so the cutting wheel 32 cuts a similar profile in the blank 16.At the end of the traverse the cam 20 allows the arms 6 and 8 to rise and the traverse cam allows bar 2 to slide to the right in Figure 2 and the cam operated switch switches off the machine.

The sample key and the newly cut key are removed from the clamps 10 and the machine is ready for a further operation. It will be appreciated that the machine can be operated with relatively unskilled labour and can be left unattended once a key and blank have been clamped in correct position and the start switch operated. The pressure of the key blank against the cutting wheel 32 is controlled by the parameters of the system which can be arranged to avoid overloading of the cutting wheel. The stopping of the cutting wheel at the end of the cycle is an added safety factor.

WHAT WE CLAIM IS: 1. A key cutting machine of the type aforesaid comprising power means for moving the probe and key holder from spaced apart start positions towards one another transversely to the length of a key held, in use of the machine, in said holder the path of said movement being in an arc about an axis parallel both to the plane of said key and to the rotary axis of the cutting means.
2. A key cutting machine as claimed in Claim í wherein said power means effect, subsequent to said movement, further relative movement between the probe and the key holder automatically and successively (a) in one direction of the length of the key in use, (b) away from one another transversely of said direction and (c) in the direction opposite to that referred to in (a).
3. A key cutting machine, according to Claim 2 adapted relatively to move the probe and key holder automatically in a complete cycle.
4. A key cutting machine according to Claim 3 wherein said power means comprises an electric motor connectible to a source of electric energy through a switch, and means to move said switch to an off position at a predetermined relative position of probe and key holder.
5. A key cutting machine according to Claim 2, Claim 3 or Claim 4 comprising cam

and follower means for controlling the relative movement of probe and key holder in one or both directions of the length of the key in use of the machine.
6. A key cutting machine according to any one of Claims 1 to 4 comprising cam and follower means for controlling the relative movement of probe and key holder transversely to the direction of the length of the key in use of the machine.
7. A key cutting machine according to Claim 4 wherein the switch moving means comprises a cam and follower.
8. A key cutting machine of the type aforesaid substantially as described with reference to the drawings.