GB2158187A - Coupling device for transmitting rotation - Google Patents

Abstract

A device 20 for rotationally coupling a screw-threaded rod 14 (for example a bolt) to a power unit (for example an electrical impact drill) is provided with means for quickly releasing the grip on the rod at the end of the driving operation. A pivoted lever 34 against which the end of the rod bears is held in position by the output member 12 of the drive unit, and the grip released when the unit is detached from the coupling device. <IMAGE>

Description

SPECIFICATION Coupling device for transmitting rotation This invention is concerned with a coupling device for transmitting rotation from a drive unit to a screw threaded rod, for example to rotate a bolt to stir and mix the contents of a two-component chemical composition contained in a capsule for anchoring the bolt in a hole in masonry, concrete or other building material.

In the use of capsule anchors, as they are known, it is desirable to provide an electric tool with a rotary output member which can be coupled to the bolt to rotate it for the stirring operation. If the bolt is merely threaded into a coupling device which can be driven by the output member of the tool, it will happen, unless special steps are taken, that the bolt will become tightly screwed against whatever abutment is provided to stop the coupling device running indefinitely along the bolt, making it difficult to disengage the coupling device from the bolt after mixing the composition, especially while, as will invariably be the case, the composition is still soft.

It has been proposed to provide a coupling device with an adjustable stop to abut the end of the bolt, and to move the stop to relieve the pressure on the end of the bolt after mixing in order that the bolt can be readily unscrewed, but such proposals have usually involved the use of an additional tool to effect the necessary adjustment and inconvenience in handling the power unit and bolt without disturbing the as yet unset composition.

It is one of the objects of this invention to provide an improved coupling device which it is simple and quick to release from a bolt after rotating to stir and mix the contents of the capsule of a capsule anchor.

The invention provides a coupling device for transmitting rotation from a drive unit to a screw-threaded rod comprising a body having an internally screw-threaded sleeve portion at one end and means at the other end for driving engagement with a rotary output member of the drive unit, the coupling device also comprising an end stop engagable by the end of the screw threaded rod and pivoted to the body by a pin lying in a direction transverse to the axis of such rod and rockable about such pin into and out of an operative position for abutment with the end of a rod threaded into the sleeve portion, the end stop being held in said operative position when the drive unit is in use by engagement of an upstanding arm of the end stop with a driving face of the output member of the drive unit and releasable from said operative position upon disengagement of the drive unit from the coupling device so that the coupling device can be readily unscrewed from the rod.

Preferably, in a coupling device in accordance with the invention the upstanding arm of said end stop constitutes part at least of a wall portion of a tongue and slot interconnection between the coupling device and the drive unit. The upstanding arm of said end stop may be disposed at the opposite side of the axis from the pivot pin and constitutes part of one wall of a slot arranged to accommodate a tongue of the drive unit, such tongue when in the slot holding the end stop in its operative position. Alternatively, the upstanding arm may lie on the axis of the sleeve portion so that it can be received in a slot in the output member of the drive unit.

Preferably, in a device in accordance with the invention the slot is sufficiently elongated, for example open ended, to enable disengagement of the tongue after rotation to be facilitated by a rocking action of the drive unit without disturbing the composition in which the anchor has been placed. The end stop may have two portions at an angle to one another, one portion receiving the pivot pin and providing the abutment for the screw threaded rod, and the other constituting said upstanding arm.

There now follows a detailed description, to be read with reference to the acompanying drawings, of two coupling devices embodying the invention and illustrative thereof. It will be realised that these illustrative devices has been selected for description by way of example not of limitation of the invention.

In the accompanying drawings: Figure 1 is a view in central longitudinal section of the first illustrative coupling device, shown in engagement with an output member of a drive unit and with a screw-threaded bolt in it; Figure 2 is a view of the device shown in Fig. 1, but after release of the output member at the end of a stirring operation; Figure 3 is an axial view from above (viewing Fig. 1) of the first illustrative coupling device; Figure 4 is a view in section on the line Ill-Ill of Fig. 1; and Figures 5, 6 and 7 are views similar to Figs. 1, 2 and 3 respectively but showing the second illustrative device.

Referring first to Figs. 1, 2, 3 and 4, the illustrative coupling device 10 there shown is designed for the purpose of transmitting rotation from an output member 1 2 of a drive unit (not shown) of a rotary power tool, for an impact electric drill, to a bolt 14, for example for stirring and mixing the chemical composition of a capsule (not shown) for anchoring the bolt in a hole in masonry, concrete or the like. The output member 1 2 has a tongue which serves as a dog 16 and which is rectangular with a cylindrical tip 1 8 of smaller diameter than the width of the dog. The output member 1 2 may have a shaft portion 1 3 (as illustrated in Fig. 1) to engage a chuck of the tool.

The coupling device 10 comprises a body 20 having at one end (the lower end as depicted in the drawings) a lower sleeve portion 22 having an internally screw-threaded bore 23 to receive the bolt 13, and at its other end means for driving engagement with the dog 1 6 of the output member 1 2 of the drive unit. For this purpose, the upper portion 24 of the body is cylindrical with a plain bore 26 in continuation of the threaded one of the portion 22, traversed by a diameterical slot 28 to receive the dog 1 6. The width of the slot 28 equals the diameter of the bore 26.

The dog 1 6 is of a width to fit easily in the slot 28, with its cylindrical tip portion projecting freely into the bore 26.

Also in the upper portion 24 of the body 20 of the device 10 is a second slot 30 (Figs.

2, 3 and 4) somewhat narrower than the diameter of the bore 26 and extending through the wall of the portion 24 up one side of the bore, diametrically opposite the lower end of which is a radial flat-sided hole 32. An L-shaped end stop 34 is accommodated in the slot 30, one upstanding limb 35 of it extending along the slot itself and the other being pivoted to the body by a pin 36 extending transversely to the direction of the axis of the bore 26. The axis of the pin 26 is further from the axis of threaded bore 23 in the sleeve portion 22 than the radius of the bore, so that an under side of the stop 34 which lies opposite the threaded bore 23 will move towards and away from the end of that bore as the stop rocks about the pin.The bottom of said second slot 30 (visible at 38 in Fig. 2) serves as an abutment to limit rocking of the stop in a clockwise direction (viewing Filgs. 1 and 2), thus to determine approximately the operative position of the under face of the end stop 34, which is abutted by the end of the bolt 14.

Conveniently, in using the coupling device 10, the bolt 14 may first be threaded into the sleeve portion 22 and the device engaged with the output member 1 2 of the drive unit by inserting the dog 1 6 in the slot 28 until the tip 18 is received in the bore 26 to prevent accidental disconnection. The assembly can then be presented to a capsule which has been inserted in a hole in which the bolt is to be anchored, the capsule broken by the end of the bolt and the device rotated with the bolt to stir and mix the contents of the capsule.In doing so, the device 10 tightens on to the bolt 14, the upper end of which is forced hard against the bottom 38 of the end stop 34, the upstanding limb 35 of which consequently bears on the side of the dog 16, thrusting it against the opposite wall of the slot 28 and thereby prevents the stop rocking further about the pin 36.The pin 36, however, is preferably, as shown in Figs. 1 and 2, closer to the transverse plane in which the bottom of the stop 34 lies than it is to the inner face of the limb 35 (which engages the dog 16), so that the force resisting disengagement of the output member 12 from the body 20 of the coupling device, that is to say the friction between the sides of the dog and the inner wall of the slot 28 at one side and the limb 35 of the stop 34 on the other, is not so great as to render it difficult to detach the member 1 2 without disturbing the position of the bolt in the still soft incured chemical composition.Such detachment, which can most readily be effected by rocking the member 12 in the plane of the slot 28 (the slot being open ended (as shown) or at least long enough to permit such rocking), usually immediately releases the stop 34 so that it is free to rock up about the pin 36, no longer exerting pressure on the end of the bolt 14 and enabling the body to be easily unscrewed from the bolt. It will be seen from Fig. 1 that the slot 28 is not quite as deep as the dog 1 6 so that there is a gap between the upper surface of the portion 24 and the lower surfaces of the member 1 2 at either side of the dog 1 6 so that a screwdriver blade or similar suitable tool can be inserted between them to assist levering them apart should they offer excessive resistance to release.

The device 10 thus achieves its purpose while being of simple robust design. Consisting of only two parts pivoted together it is economical to manufacture.

In Figs. 5, 6 and 7 is shown the second illustrative device, also embodying the invention, which can be used in the same way.

Corresponding parts are identified by the same reference numerals with one hundred added. In this alternative construction, it is the body 1 20 of the device 110 which provides the tongue, or dog, 116 for driving engagement with an output member 11 2 which has a slot 1 28 to receive it. The upper limb 1 35 of the end stop 1 34 is located on the axis of the bore 123, in a second slot 1 30 in the dog 11 6. In this case, the face of the limb 1 35 which abuts the output member 11 2 is in a plane as close to the pivot pin 1 36 as is the bottom of the stop, but nonetheless, detachment of the drive unit is not unduly impeded. The output member 11 2 is shown with an hexagonal recess 11 5 rather than a shaft as 1 3 of Fig. 1 for driving engagement with the rotary tool.

The second illustrative device is otherwise similar in construction and operation to the device 10.

Claims (8)

1. A coupling device for transmitting rotation from a drive unit to a screw-threaded rod comprising a body having an internaly screwthreaded sleeve portion at one end and means at the other end for driving engagement with a rotary output member of the drive unit, the coupling device also comprising an end stop engagable by the end of the screw threaded rod and pivoted to the body by a pin lying in a direction transverse to the axis of such rod and rockable about such pin into and out of an operative position for abutment with the end of a rod threaded into the sleeve portion, the end stop being held in said operative position when the drive unit is in use by engagement of an upstanding arm of the end stop with a driving face of the output member of the drive unit and releasable from said operative position upon disengagement of the coupling device from the drive unit so that the coupling device can be readily unscrewed from the rod.

2. A coupling device according to claim 1 in which the upstanding arm of said end stop constitutes part at least of a wall portion of a tongue and slot interconnection between the coupling device and the drive unit.

3. A coupling device according to claim 1 in which the upstanding arm of said end stop is disposed at the opposite side of said axis from the pivot pin and constitutes part of one wall of a slot arranged to accommodate a tongue of a drive unit, such tongue when in the slot thus holding the end stop in its operative position.

4. A coupling device according to claim 3 in which said slot is open ended to enable disengagement of the tongue after rotation to be facilitated by a rocking action of the drive unit.

5. A coupling device according to claim 4 in which said end stop has two portions at an angle to one another, one portion receiving the pivot pin and providing the abutment for the screw threaded rod, and the other constituting said upstanding arm.

6. A coupling device according to claim 2 in which the upstanding arm of said end stop lies on the axis of said sleeve portion so that it can be received in a slot in the output member of the drive unit.

7. A coupling device according to claim 6 in which the upstanding arm of said end stop is accommodated between two upstanding walls of the coupling device, which two walls together with said upstanding arm constitute the tongue of said interconnection.

8. A coupling device substantially as herein before described with reference to (a) Figs. 1, 2 and 3, or (b) Figs. 4, 5 and 6 of the accompanying drawings.