GB2157204A - Sprung chuck key - Google Patents

Abstract

A sprung chuck key, has a handle 10 on which is fixed a pinion 18 through which passes a coaxial co-operating pin 14 that is sprung so that it is normally retracted within the pinion. Button 13 is provided so that the operator may push the pin into its working position, out of the pinion. The coiled compression spring 15 is coaxial with the shaft of the pin. Due to the action of the spring against the annular shoulders 16 & 17, withdrawing the pin into the pinion, the chuck key may not remain in position on the chuck which it fits unless pressure is applied to the button. A hole 20 is provided in the handle so that the chuck key may be attached on or near the equipment that uses it. A recess 19 is provided within the handle to enhance the grip. <IMAGE>

Description

SPECIFICATION Sprung chuck keys The present invention concerns sprung chuck keys for use on hand drills or lathes.

Accidents can occur due to forgetting a chuck key in place when a machine is turned on.

An object of the present invention is to provide a key which will be automatically removed when not in the operative position.

According to the present invention a chuck key is provided with an engaging plunger adapted to be automatically disengaged from the machine when pressure on the plunger is withdrawn. Preferably the disengaging mechanism comprises a compression spring bearing on a collar in the plunger housing.

The invention will now be described further, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a side elevation of a chuck key and associated housing constructed in accordance with the present invention; and Figure 2 is a corresponding plan.

The key shown in the drawings comprises a handle 10 having a cylindrical portion 11 and an arm 12 diagonally opposite the handle 10 on the cylindrical portion 11. The cylindircal portion 11 houses a plunger assembly comprising a plunger button 13 at the forward end of which is provided an engaging pin 14. A compression spring 15 is arranged between an annular shoulder 16 at the lower end of the plunger button 13 and an annular shoulder 17 provided inside the cylindrical portion of the handle 10.

The lower end of the cylindrical portion 13 is formed into a pinion 18 for engagement with the teeth of a chuck. The arm 12 is provided with a thumb recess 19 whilst a cord hole 20 is provided in the handle 10 to enable the key to be attached near or on the equipment that uses it. It has been found that an angle of 100 between the axis of the handle and the axis of the plunger is the most suitale.

The handle 10, cylindrical portion 11, arm 12 and plunger button 13 can be mouldings of tough synthetic material but the pin 14 and pinion 18 are preferably made of steel.

Figure 1 shows the plunger pin 14 in the engaged position. When pressure on the button 13 is released the pin 14 will retract under action of the compression spring 15.

It can be seen that the key assembly can not remain in the chuck unless held there by the operator. A handle of this type gives a better grip and more leverage than known types of key.

1. A sprung chuck key comprising a handle, fixed to a pinion through which passes a coaxial co-operating pin adapted to be held within the pinion by a spring. Pressure applied to that part of the pin opposite to the end in the pinion, causes it to be pushed out from the pinion. When pressure is removed, the pin is withdrawn into the pinion by the action of the spring.

2. A sprung chuck key as claimed in Claim 1 wherein the spring is coaxial with the pin.

3. A sprung chuck key as claimed in Claim 1 or Claim 2 where in a button is provided to displace the pin against the spring.

4. A sprung chuck key as claimed in Claim 3 wherein the linear travel of the pin is guided by the pinion and also by guide means in the handle.

5. A sprung chuck key substantially as described herein with reference to Figures 1-2 of the accompanying drawing.

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

Claims (5)

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Sprung chuck keys The present invention concerns sprung chuck keys for use on hand drills or lathes. Accidents can occur due to forgetting a chuck key in place when a machine is turned on. An object of the present invention is to provide a key which will be automatically removed when not in the operative position. According to the present invention a chuck key is provided with an engaging plunger adapted to be automatically disengaged from the machine when pressure on the plunger is withdrawn. Preferably the disengaging mechanism comprises a compression spring bearing on a collar in the plunger housing. The invention will now be described further, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a side elevation of a chuck key and associated housing constructed in accordance with the present invention; and Figure 2 is a corresponding plan. The key shown in the drawings comprises a handle 10 having a cylindrical portion 11 and an arm 12 diagonally opposite the handle 10 on the cylindrical portion 11. The cylindircal portion 11 houses a plunger assembly comprising a plunger button 13 at the forward end of which is provided an engaging pin 14. A compression spring 15 is arranged between an annular shoulder 16 at the lower end of the plunger button 13 and an annular shoulder 17 provided inside the cylindrical portion of the handle 10. The lower end of the cylindrical portion 13 is formed into a pinion 18 for engagement with the teeth of a chuck. The arm 12 is provided with a thumb recess 19 whilst a cord hole 20 is provided in the handle 10 to enable the key to be attached near or on the equipment that uses it. It has been found that an angle of 100 between the axis of the handle and the axis of the plunger is the most suitale. The handle 10, cylindrical portion 11, arm 12 and plunger button 13 can be mouldings of tough synthetic material but the pin 14 and pinion 18 are preferably made of steel. Figure 1 shows the plunger pin 14 in the engaged position. When pressure on the button 13 is released the pin 14 will retract under action of the compression spring 15. It can be seen that the key assembly can not remain in the chuck unless held there by the operator. A handle of this type gives a better grip and more leverage than known types of key. CLAIMS

1. A sprung chuck key comprising a handle, fixed to a pinion through which passes a coaxial co-operating pin adapted to be held within the pinion by a spring. Pressure applied to that part of the pin opposite to the end in the pinion, causes it to be pushed out from the pinion. When pressure is removed, the pin is withdrawn into the pinion by the action of the spring.

2. A sprung chuck key as claimed in Claim 1 wherein the spring is coaxial with the pin.

3. A sprung chuck key as claimed in Claim 1 or Claim 2 where in a button is provided to displace the pin against the spring.

4. A sprung chuck key as claimed in Claim 3 wherein the linear travel of the pin is guided by the pinion and also by guide means in the handle.

5. A sprung chuck key substantially as described herein with reference to Figures 1-2 of the accompanying drawing.