DE9107860U1 - Automatic assembly machine - Google Patents

Description

A 50 067/68 b Dixon Automatic Tool, Inc.

k-189 2300 23rd Avenue

June 17, 1991 Rockford, Illinois 61108-7393

USA

Automatic assembly machine

The invention relates to an assembly machine with a carrier which has a first part and a second part which is horizontally adjustable relative to the first part, with an automatic drive device for driving fastening elements, in particular with a screwdriver, with assembly devices for mounting the drive devices on the second part of the carrier in such a way that the drive devices can be moved up and down between an upper rest position and a lower working position, whereby the assembly devices secure the drive devices to the second part of the carrier in a rotationally fixed manner, with a power-operated actuating device arranged between the drive devices and the second part of the carrier, which can be selectively actuated in order to move the drive devices up and down between their end positions, and with manually operable adjusting devices for adjusting the drive devices and the second part of the carrier in the horizontal direction with respect to the first part of the carrier and for controlling the actuating device to bring about the up and down movement of the drive devices, whereby the manually operable Adjustment devices have a downwardly directed actuating handle, which is movable together with the second part of the carrier, and which has a handle part which can be grasped by hand and can be moved by hand in a horizontal

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direction to effect a horizontal adjustment of the drive devices and the second part of the carrier with respect to the first part of the carrier.

In particular, the invention relates to an assembly machine comprising an automatic "screwdriver" for attaching screws, nuts and similar threaded parts to a workpiece.

Automatic assembly machines of this type are described in U.S. Patents 3,279,045, 3,675,302 and 3,910,325. The drive means or drivers of these machines comprise a rotary drive motor operable to drive a screwdriver bit, a socket for screwing nuts or a similar tool in a rotary motion, the fasteners being fed to the tool one by one.

Assembly machines of the type in question are used in such a way that the screwdriver or the like is moved horizontally into the correct position above a workpiece and then moved downwards to connect the screw or the like to the workpiece. The screwdriver is then retracted upwards and moved horizontally into a new position above the workpiece in preparation for the next screwing operation.

The screwdriver described in US-PS 3,910,325 is in principle a hand-held power tool that is extremely flexible in terms of its positioning. However, since the screwdriver is operated by hand

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is held, the operator must bend the wrist when a fastener is screwed down using the motor-driven tool. If you work for a long time with this well-known tool, the constant bending of the wrist can lead to what is known as carpal tunnel syndrome.

In the devices of US Patents 3,279,045 and 3,675,302, the operator grasps a handle-like element to move the tool into different positions and presses a push-button switch with his thumb to cause the up and down movements of a power-operated actuator. The push-button switch is located above the handle-like element and it is tiring and inconvenient to press this switch over and over during a long work day.

Based on the state of the art and the problems outlined above, the invention is based on the object of improving an assembly machine of the type specified at the outset in such a way that working on the machine is made easier for the operator.

This object is achieved in a generic assembly machine according to the invention in that mounting devices are provided to which the operating handle is fastened in such a way that it can be moved up and down relative to the drive devices between an upper rest position and a lower working position, that pre-tensioning devices are provided with the aid of which the operating handle is pre-tensioned upwards into its rest position, and that devices are provided

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by means of which the actuating device can be brought into its working position in dependence on a downward movement of the actuating handle in order to move the drive devices downwards into their working position, and by means of which the actuating device can be brought into its rest position in dependence on an upward movement of the actuating handle in order to move the drive devices upwards into their rest position.

It is a particular advantage of the assembly machine according to the invention that an operating handle is provided with which not only the positioning of the screwdriver or the like is possible, but also the control of the operating device for raising and lowering the drive devices, which makes working on the machine easier and more convenient overall.

It has proven particularly advantageous in an embodiment of the invention to integrate a control valve, in particular a pilot valve, into the actuating handle in such a way that it responds directly to the upward and downward movements of the handle in order to actuate the actuating device for bringing about the upward and downward movements of the screwdriver or the like.

Further details and advantages of the invention are explained in more detail below using a preferred embodiment in conjunction with drawings. They show:

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Fig. 1 is a perspective view of a preferred embodiment of an assembly machine improved according to the invention;

Fig. 2 is a side view of the machine according to Fig. in its upper end position, which forms the rest position;

Fig. 3 one of the representation according to Fig. 2

corresponding representation with the machine in its lower end position, corresponding to the working position;

Fig. 4 is a partial side view of the machine according to

Fig. 3, viewed from line 4-4 in this figure;

Fig. 5 is an enlarged partial plan view of the

The assembly of Figure 4, viewed from line 5-5 in that figure, with some parts broken away and others shown in section;

Fig. 6 is a cross-sectional view of the arrangement of Fig. 4 taken along line 6-6 in that figure;

Fig. 7 one of the representation according to Fig. 6

corresponding cross-sectional view, but with the operating handle in its working position; and

Fig. 8 is a schematic diagram of a

pneumatic circuit to control the up and down movements of a screwdriver of the assembly machine.

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For purposes of explanation, the invention is shown in the drawing as it may be implemented in an automatic assembly machine 10 operable to drive or screw threaded fasteners (not shown) into a workpiece 11 (Fig. 3). Although the machine may process various types of fasteners, typically the fasteners are screws.

The machine 10 includes an automatic fastener driver - hereinafter referred to for convenience as a screwdriver 15 - which includes a pneumatic rotary drive motor 16 operable to drive a tool bit - hereinafter referred to as a bit 17 (Fig. 8) - to rotate. The screws are fed through a feed tube 19 (Fig. 4) to a clamping device 20, driven to rotate by the bit 17 and screwed into the workpiece 11 when the screwdriver 15 is moved downwards to a working or driving position as shown in Fig. 3. After screwing in a screw, the screwdriver 15 is returned upwards to a starting or rest position (Fig. 2) and repositioned horizontally in a different position above the workpiece, thus preparing for the screwing in of the next screw into the workpiece.

In many respects, the screwdriver 15 is supported in a similar manner to the screwdriver in Fig. 22 and 23 of US-PS 3,675,302. In particular, a base 22 is provided with a vertical stand 21 on which a horizontal arm 23 formed as a cast part can be pivoted

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is held. A vertical rod or axis 24 is provided at the free end of the arm 23. A second horizontal arm 25, designed as a cast part, is pivotally held by the axis 24 and has at its free end two horizontal arms 26 arranged at a distance from one another in the vertical direction, which carry the screwdriver 15. The two arms 23 and 25 thus form an articulated arm, which can be pivoted as a whole around the stand 21 and whose parts can be pivoted against one another around the axis 24, so that the screwdriver 15 can be positioned laterally and forwards and backwards in the horizontal direction and can thus screw screws into a workpiece at different points.

The screwdriver 15 is rigidly attached to a carriage 30 which in turn is supported so as to be movable up and down along vertical rods 32 which are connected to and extend between the arms 26. The upward and downward movement of the carriage 30 is effected by means of a pneumatic actuator 33, the cylinder 34 of which is supported by one of the arms 26 and which has a downwardly directed piston rod 35 (Fig. 3) whose lower end is connected to the carriage 30. When compressed air is supplied to an upper chamber 36 (Fig. 8) of the cylinder 34, the carriage 30 and the screwdriver 15 are moved downwards from the starting position according to Fig. 2 to the working position according to Fig. 3 during the working stroke. If, on the other hand, the compressed air is supplied to a lower chamber 37 of the cylinder, this results in a return movement of the carriage 30 and screwdriver 15 upwards into the rest position shown in Fig. 2.

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According to the invention, the machine 10 is provided with a downwardly directed handle or operating handle 40, which serves not only to move the screwdriver 15 horizontally into different positions, but also to actuate the operating device 33 and thereby control the up and down movement of the screwdriver 15. The operating handle 40 is particularly characterized in that it is extremely comfortable for the operator of the machine to use and enables the machine to be operated for long periods of time without this being particularly tiring or uncomfortable for the user and without the user's hand and wrist having to perform movements which could lead to the so-called "carpal tunnel" syndrome.

In detail, the handle 40 according to Figs. 4 and 5 is attached to the underside of a bracket 41 which has an upper and a lower horizontal arm 42, the two arms 42 being rigidly attached to the carriage 30. The arms 42 are provided, as can be seen in Fig. 5, with recesses 43 which form a seat for the screwdriver 15. A bracket 46 with a similar recess or recess 47 is arranged on the side of the screwdriver 15 opposite the arms 42 in such a way that it is located vertically between the two arms 42 and cooperates with them to define a seat for the screwdriver 15. Screws 48 secure the clamp 46 to the carriage 30, and when the screws 48 are tightened, the screwdriver 15 is clamped between the arms 42 and the clamp 46 such that it is rigidly secured to the carriage 30.

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As best seen in Fig. 6, the operating handle 40 has a handle part 50 made of plastic, for example of a vinyl resin, which is provided on one side with recesses (grip recesses) 51 which serve to accommodate the fingers of an operator.

The elastic grip part 50 sits tightly on a tubular core 53 (Fig. 6), which in turn can slide telescopically over an inner bushing 54. The bushing extends downwards from the bracket 41, with its upper end being rigidly fixed by means of an adjusting screw 55 in a hole 56 in the lower end region of the bracket 41.

In the implementation of the invention, the operating handle 40 is assigned a pilot or control valve 60 (Fig. 6 to 8), which can be actuated by the upward and downward movements of the handle part 50 relative to the bushing 54. In the exemplary embodiment, the valve comprises an elongated shaft 61 which slides through the lower end of the bushing 54 and whose lower end is inserted into the bottom of the core 53 and is secured there by means of an adjusting screw 62. A disk 63 at the upper end of the shaft 61 is normally located at the upper end of the bore 56 and is normally pressed upwards against the bracket 41 by means of a coil spring 64 which surrounds the shaft 61 and is compressed between the disk 63 and a part of the fixed bushing 54.

A coil-shaped valve body 65 (Fig. 6 to 8) is attached to the shaft 61 above the disk 63 and can be slid up and down in a valve housing 66 which is attached to the bracket.

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An upper extension 67 of the shaft is guided in a sliding manner through a bushing 68 which is inserted into a cap 69 at the upper end of the bracket 41, which is secured there by an adjusting screw 70.

The valve housing 66 is provided with two axially spaced valve openings 71 and 72 (Fig. 6) which are connected to fittings 73 and 74 provided with retaining webs (barbs), which in turn can be connected to flexible compressed air hoses. Compressed air from a compressed air source 75 (Fig. 8) can be supplied to the valve housing 66 via the fitting 73 and the opening 71. When the operating handle 40 assumes its normal unactuated position, which is shown in Fig. 6, then O-rings 76 on the valve body 65 seal the opening 71 from the opening 72 and prevent a flow of compressed air to the opening 72. When the valve body assumes this position, the opening 72 is connected to the atmosphere via a channel 77 in the housing 66 and the bracket 41. If the operating handle 40 is now pulled downwards into its working position shown in Fig. 7, then the valve body 65 is thereby adjusted downwards so that compressed air can flow from the opening 71 through the opening 72 out of the fitting 74.

When working with the machine 10, the operator holds the operating handle 40 and moves the screwdriver 15 using the handle in a horizontal plane to a desired position above the workpiece 11. After the screwdriver 15 is positioned in the horizontal plane, the operator pulls the operating handle 40 downwards to release the valve body

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65 from the position shown in Fig. 6 to the position shown in Fig. 7. Consequently, compressed air from the compressed air source 75 is supplied from the opening 71 of the second opening 72 and directed to the actuator 80 (Fig. 8) of a spring-loaded relay valve 81, thereby adjusting the valve element of this valve. The compressed air from the compressed air source 75 is then supplied to the upper chamber 36 of the actuator 33 to move the screwdriver 15 downward in a working stroke.

Once the screw in question has been tightened, the operator pushes the actuating handle 40 upwards so that the valve body 65 returns to its position shown in Fig. 6. This vents the actuator 80 of the relay valve 81 to the atmosphere via the channel 77 of the control valve 60. The relay valve 81 then returns under the action of a return spring to the position shown in Fig. 8 to vent the upper chamber 36 of the actuator 33 and direct the compressed air to the lower chamber 37. The screwdriver 15 is thus retracted in the horizontal direction in preparation for repositioning.

If the operator releases the operating handle 40 at any time during the working stroke, the spring 64 pushes the valve body 65 upwardly to cause the screwdriver 15 to be raised. The screwdriver 15 is thus automatically retracted if the operator loses his grip on the operating handle or if a quick retraction is required to prevent jamming or injury.

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From the foregoing description, it is clear that an operating handle 40, which is used to move the screwdriver 15 in a horizontal direction, is simultaneously used to control the up and down movement of the screwdriver. The operating handle 40 increases the ease of use and avoids the need to switch, for example with the thumb, in order to bring about an upward or downward movement.

While the screwdriver 15 has been described above specifically in connection with an articulated support arm 23, 25, those skilled in the art will recognize that the screwdriver could also be attached to a coordinate guide. Furthermore, the operating handle 40 could be used to directly adjust a main control valve for the actuator 33 or to operate other types of control devices for an up/down actuator. Furthermore, instead of being attached to the carriage 30 and being moved up and down with it, the operating handle 40 could be attached to the support arm 25.

Claims (7)

A 50 067/68 b k-189 - 13 - 17 June 1991 Claims 1. Assembly machine with a carrier which has a first part and a second part which is horizontally adjustable relative to the first part, with an automatic drive device for driving fastening elements, in particular with a screwdriver, with assembly devices for mounting the drive devices on the second part of the carrier in such a way that the drive devices can be moved up and down between an upper rest position and a lower working position, whereby the assembly devices secure the drive devices to the second part of the carrier in a rotationally fixed manner, with a power-operated actuating device arranged between the drive devices and the second part of the carrier, which can be selectively actuated in order to move the drive devices up and down between their end positions, and with manually operable adjusting devices for adjusting the drive devices and the second part of the carrier in the horizontal direction relative to the first part of the carrier and for controlling the actuating device to bring about the up and down movement of the drive devices, whereby the manually operable Adjustment devices have a downwardly directed operating handle which is movable together with the second part of the carrier, and which has a handle part which can be grasped by hand and moved by hand in a horizontal A 50 067/68 b k-189 - 14 - 17 June 1991 Direction can be pushed or pulled to effect a horizontal adjustment of the drive devices and the second part of the carrier with respect to the first part of the carrier, characterized in that mounting devices (41) are provided to which the operating handle (40) is fastened in such a way that it can be moved up and down relative to the drive devices (15) between an upper rest position and a lower working position, that pretensioning devices (64) are provided by means of which the operating handle (40) is pretensioned upwards into its rest position, and that devices (60, 80, 81) are provided by means of which the operating device (33) can be brought into its working position in dependence on a downward movement of the operating handle (40) in order to move the drive devices (15) downwards into their working position, and by means of which the operating device (33) can be brought into its rest position in dependence on an upward movement of the operating handle (40) in order to move the drive devices (15) upwards to its rest position. 2. Assembly machine according to claim 1, characterized in that the operating handle (40) has a substantially cylindrical central core (53) and a plastic handle part (50) which is fitted onto the core (53), and that one side of the handle part (50) is provided with a plurality of grip recesses (57) for receiving the fingers of an operator. A 50 067/68 b k-189 - 15 - 17 June 1991 3. Assembly machine according to claim 1, characterized in that the power-operated actuating device has a pneumatic actuating device (33) for bringing about a reciprocating movement and that the devices responsive to vertical movements of the handle (40) comprise a control valve (60) which is connected to a compressed air source, that a relay valve (81) is additionally provided which is connected to a compressed air source and which can be actuated by the control valve (60) to control the actuating device (33). 4. Assembly machine according to one of claims 1 to 3, characterized in that the two parts (23, 25) of the carrier are pivotable relative to each other about a vertical axis (24). 5. Assembly machine according to one of claims 1 to 4, characterized in that the actuating device (33) is designed as a pneumatic device for bringing about a back and forth movement, which has an upper chamber (36) and a lower chamber (37) and with the aid of which the drive devices (15) can be lowered into their working position when compressed air is supplied to one of the chambers (36), while the drive devices (15) can be raised into their rest position when the compressed air is released from this one chamber (36). 6. Assembly machine according to claim 5, characterized in that the devices for adjusting the actuating device depending on A 50 067/68 b k-189 - 16 - 17 June 1991 Upward and downward movements of the operating handle (40) have a control valve (60) which has a valve element (65) which is movable into a first position in order to supply compressed air to one chamber (36) and into a second position in order to discharge the compressed air from one chamber (36), and that the valve element (65) is movable up and down with the operating handle (40). 7. Assembly machine according to claim 6, characterized in that the control valve (60) is designed as a pilot valve for a relay valve (81) connected to the actuating device (33).