WO2023131820A1

WO2023131820A1 - Automatic screw feeding and alignment system design

Info

Publication number: WO2023131820A1
Application number: PCT/IB2022/050538
Authority: WO
Inventors: André Armindo SAMPAIO DE ABREU FERNANDES; André Manuel CARDOSO LIMA; Álvaro Miguel DO CÉU GRAMAXO OLIVEIRA SAMPAIO; António José VILELA PONTES; Luís Carlos NETO MARTINS; Eurico José DE MIRANDA DAMÁSIO; João Paulo PINTO DA COSTA; Hélder GASPAR OLIVEIRA GIESTEIRA; Fábio André MARTINS FERNANDES; Daniela Sofia SOUSA RODRIGUES
Original assignee: Bosch Car Multimedia Portugal, S.A.; Universidade Do Minho
Priority date: 2022-01-04
Filing date: 2022-01-21
Publication date: 2023-07-13

Abstract

The present invention describes an automatic screw feeding and alignment system (100) that can be adapted to an automatic and manual screwdriving processes. This system allows the individual and automatic screws feeding between each screwing cycle and ensure the alignment between the screwdriver (200) and the screw during the tightening process in order to reduce cycle time, eliminating the necessity to pick and place the screw.

Description

Automatic screw feeding and alignment system design

Technical Field

The present invention describes an automatic screw feeding and alignment system that can be adapted to an automatic and manual screwdriving processes .

Background art

Document US2670770A discloses a portable power-driven tool of the rotary type and more particularly to automatic screw drivers , which incorporates , means for holding the screw rigidly during the first part of the driving operation, which is fully automatic in action and handles without error all screws having a variable range of dimensions within commercial tolerances . In addition, this system is supposed to be portable , light and easy to operate as well as to manufacture .

Document US3587683A describes an automatic screwdriver composed by a head with a movable section, which retracts in order to allow the screwdriver blade to urge against a screw placed in the screwdriver and that moves to allow the feeding of the screw into the head, such as it happens in this invention .

Document EP0014529A1 describes another automatic power- driven screwdriver with a characteristic feed tube in a angular position for screws and bolts . In this one , the nose portion of the apparatus can be rotated to any desired angular position with respect to the hand grip portion so that a screw feeder tube can be positioned to avoid any obstacle which might be present in the area of use .

Document US 8230570B1 a linkage of an electric screwdriver with an automatic screw feeding adaptor is exhibited . After being received the first screw within the screw feeding adaptor, the screw is held at a driving position by applying partial vacuum . Then, the screw is driven, and a torque is applied . After that , another screw moves along the screw path .

Summary

The present invention describes an automatic screw feeding and alignment system for a screwdriver set comprising a screwdriver fixing support ; a centering bush and a holder ; characteri zed by the centering bush being mechanically fitted to the holder, and said holder being adapted to the screwdriver fixing support through a two shaft-bearing set comprised of linear motion bearings and precision linear shafts ; wherein the shaft-bearing sets ensures a uni form parallel relative movement between the screwdriver fixing support and the holder , and the centering bush comprises protrusions configured to ensure the correct alignment of a bit driver installed in the screwdriver set and a screw installed inside the centering bush during the movement between the screwdriver fixing support and the holder .

In a proposed embodiment of present invention, the screwdriver fixing support comprises a "U" shaped format adapted to fit a screwdriver set through its basis and said support comprises protrusions on the extremities of the "U" shaped format to promote the fitting of the linear motion bearings .

Yet in another proposed embodiment of present invention, the holder comprises two mechanical connection supports , mechanical connection support A and mechanical connection support B, aligned with the extremities of the "U" shaped format of screwdriver fixing support , adapted to mechanically secure one end of each linear shaft through screw fittings .

Yet in another proposed embodiment of present invention, the centering bush comprises "Y" shaped format with a screwdriver admission connection, a pneumatic admission connection and an output connection, wherein the screwdriver admission connection is centred and aligned with the output connection, promoting the connection between the bit driver and the screw .

Yet in another proposed embodiment of present invention, the pneumatic admission connection promotes a perpendicular admission of at least a screw in the centering bush that will be further aligned with bit driver on the output connection .

Yet in another proposed embodiment of present invention, the pneumatic admission connection of centering bush is centrally positioned with regard to the holder and to the screwdriver fixing support .

Yet in another proposed embodiment of present invention, the screwdriver fixing support is obtained through additive manufacturing procedure and comprises a combination of polymeric and metallic materials .

Yet in another proposed embodiment of present invention, the holder is obtained through an additive manufacturing procedure and comprises a combination of polymeric materials .

Yet in another proposed embodiment of present invention, the centering bush is obtained through a subtractive or additive manufacturing procedure and comprises a combination of metallic materials .

The present invention further describes operating method of the automatic screw feeding and alignment system for a screwdriver set according to above-described system, comprising the steps of a screw being blown through the pneumatic admission connection into the centering bush; the screw being positioned in a lower position of the centering bush, will be aligned within the centering bush with a bit driver of the screwdriver ; the bit driver, promoted by the movement of the screwdriver set mechanically connected to the screwdriver fixing support , enters through the screwdriver admission connection in a linear movement towards a screwing plane , mechanically connecting with the screw, promoting the centering blades to open due to the force imposed by the bit driver and the screw, allowing its passage in towards the screwing plane ; after the screw being screwed to the screwing surface through the rotation movement performed by the bit driver, the holder performs an opposite linear movement with regard to the screwing plane , promoting the centering bush to be unobstructed by the bit driver, allowing the admission of another blown screw through the pneumatic admission connection .

General Description

The present invention describes an automatic screw feeding and alignment system that can be adapted to an automatic and manual screwdriving processes , stations or robots .

It is well known that the process of installing a large number of screws can be exhausting and time consuming for the operator even with the help of an electric screwdriver, since it is required a correct pick up of the screws , together with a manual positioning and holding of the screw in alignment with the bit .

Further, automatic screw feeder combined with pneumatic or electric screwdriver systems have been developed in order to eliminate the need of an operator to hold the screw in place before the screwing process . Generally, this type of combined systems is composed by a head with a Y-shape connection to the feeder and to a hose . Thus , the screwing process in this type of devices is achieved by the delivering of a single screw by an air driven escapement mechanism; followed by the driving of the screw through a channel due to the advancement of the screwdriver ; and finally, the screw is fastened to the hole present in the component . The screwdriver blade retracts or extends depending on i f it is allowing the entrance of a new screw or i f it is pushing the screw to consequently, fasten it .

Considering that this type of systems was developed to speed up the production, i f it happens a j am or a mal function of any manner, a work stoppage or delay can be the result . The existing feeding and screwing systems comprise some limitations that may lead to mal function and consequently, to production delays due to the replacement process . Some of the common reported flaws are related with vertical axis misalignment between the screwdriver and the central bush; di f ficulty on setup ; decreasing the weight of the system; decreasing lead time for the manufacture of parts ; decreasing in time and effort in changing over the screw feed; development of a standard solution for manual and automatic screwing, reducing the cost of the solution .

This situation must be avoided and for that reason, this invention can give the required improvement to these systems , since the system is almost entirely produced by additive manufacturing, accelerating the production of this type of systems ; decreasing the assembly time , us ing less components ; providing a production in mass at the same time ; and allowing the exchange of only one component , such as the central bush .

Taking in account these limitations with regard to currently existing feeding and screwing systems , the present invention provides a more reliable system by ful filling and solving some of the identi fied problems through the addition of a set of technical improvements .

One of these improvements is related with mounting the centering bush directly on the screwdriver, which will provide a reduction on the number of parts required, reducing chain tolerances , leading to a smaller deviation between the bit axis of the wrench and the axis of centering bush thereby facilitating the engagement of bit with the screw . By increasing the simplicity of the proposed automatic screw feeding and alignment system, resorting to the use of fewer components , will , consequently, facilitate assembly and disassembly when needed (breakdowns , changeover, preventive maintenance ) . Mounting from the screwdriver thread facilitates this process . The number of components used in the proposed system is quite reduced when compared with existing products , promoting, therefore , a weight reduction of the overall assembly .

In addition, when using additive manufacturing, the number of processes required to manufacture each component is reduced since parts consolidation can be applied .

In regards that the assembly is done only through the screwdriver thread, changing the screw feed solution ( e . g . , vacuum or centering bush) can be done in less than 1 minute , j ust unscrewing one set and tightening another .

This solution allows to use this system for both manual and automatic screwing stations . Attaching the screwdriver to the robot arm or to the manual support is done in the same way . In case of replacement of the manual station by robot , no extra investment in the screw set is necessary, as it is compatible with both . Moreover, and despite this system was proj ected to a particular screwdriver set , it can also be easily adapted to a large number of di f ferent applications .

When totally assembled, the automatic screw feeding and alignment system provides an easy to assemble and disassemble solution, capable of being mounted directly on a screwdriver both on manual and automatic screwing stations . Combined with the increased simplicity and weightlessness , it also provides Electrostatic Discharge (ESD) protection .

Brief description of the drawings

For better understanding of the present application, figures representing preferred embodiments are herein attached which, however, are not intended to limit the technique disclosed herein .

Fig . 1 - depicts the overall structure of the automatic screw feeding and alignment system .

Fig . 2 - depicts a particular embodiment of the automatic screw feeding and alignment system, with focus on the set composed by the holder, the centering bush and the centering blades .

Fig . 3 - depicts a particular embodiment of the automatic screw feeding and alignment system, with focus on the set composed by the holder, the centering bush and the centering blades , and the method of attachment ( according to the direction of arrow) between the holder and centering bush .

Fig . 4 - depicts an upper view of the holder ( 2 ) .

Fig . 5 - depicts a particular embodiment of the centering blades .

Description of Embodiments

With reference to the figures , some embodiments are now described in more detail , which are however not intended to limit the scope of the present application . In a particular embodiment of the present invention illustrated in Figure 1, the overall structure of the automatic screw feeding and alignment system (100) for a screwdriver set (200) comprises a screwdriver fixing support (1) , a holder (2) and a centering bush (3) . Also part of the overall system there are linear motion bearings (4) , precision linear shafts (5) and centering blades (6) . Figure

2 illustrates a particular embodiment of the holder (2) , the centering bush (3) and the centering blades (6) . Since centering bush (3) and the holder (2) are mechanically attached to each other through an adapted structure, Figure

3 illustrates how both of said parts fit together (accordingly with the direction of the arrow) , being therein also depicted a pneumatic admission connection (3A) and a screwdriver admission connection (3B) . An upper view of the holder (2) is possible to visualize in Figure 4, were both of the mechanical connection supports, mechanical connection support A (2A) and mechanical connection support B (2B) , are identifiable in each of the side edges of said holder (2) . A particular embodiment of the centering blades (6) is detailed on Figure 5 which might comprise two symmetrical conical portions.

The screwdriver fixing support (1) of the automatic screw feeding and alignment system (100) will be a fixed part, which serves as a support for the bushings and will be mounted to the screwdriver (200) through a thread. The construction of the screwdriver fixing support (1) , in one of the preferred embodiments is in polymeric or metallic material, since both comply with current ESD requirements, and the thread will be made by using metallic inserts, in case of a polymeric fixing support. The purpose of the screwdriver fixing support (1) is to fix and align the set composed by the linear shafts (5) , the holder (2) , the centering bush (3) , the linear motion bearings (4) and the centering blades (6) , to the screwdriver (200) .

The holder (2) serves as a support for the centering bush (3) , which has a different configuration depending on the screw to be tightened and ensures the alignment of central axis with the screwdriver. The holder (2) can be obtained in polymeric material and will have ESD properties.

The centering bush (3) is the component responsible for receiving the bit drivers from the pneumatic admission connection (3A) and forwarding it to the centering blades (6) . It also aligns the bit drivers with the screws. This piece will be built by subtractive or additive manufacturing in metallic material, and it may vary depending on the final screw intended to be used.

Then screwdriver fixing support (1) , with a "U" shaped format with two legs, comprises two linear motion bearings (4) , installed in extremity of each leg. The holder (2) will be mechanically adapted to the screwdriver fixing support (1) through precision linear shafts (5) that promote the connection between the linear motion bearings (4) and the holder (2) . Therefore, each of the linear motion bearings (4) , installed in independent legs of the "U" shaped screwdriver fixing support (1) , is connected to a precision linear shaft (5) that is mechanically adapted to each of the sides of the holder (2) . Each of the extremities of the holder (2) comprise a mechanical connection support (2A, 2B) that promotes the fixation of each of the precision linear shafts (5) that are connected to the linear motion bearings (4) of the "U" shaped screwdriver fixing support (1) .

The two shaft-bearing sets (4, 5) , whose purpose is to ensure that the relative movement between the screwdriver fixing support (1) and the holder (2) is uniform, ensures the alignment in the axis of movement of all the components of the automatic screw feeding and alignment system, i.e., between the screwdriver fixing support (1) , the holder (2) and centering bush (3) .

Along with the two shaft-bearing sets (4, 5) , it's possible to couple different screwdriver (200) models to screwdriver fixing support (1) , which change according to the screwdriver characteristics in question (torque, speed, etc.) . In the centering bush (3) , it is also possible to connect different pneumatic tubes in pneumatic admission connection (3A) , which are used to blow screws, of different diameters. The centering bush (3) is where the screw centering blades (6) are placed, which are fixed through its geometry and an elastic 0-ring. The screwdriver bit driver enters through the screwdriver admission connection (3B) . Consequently, the centering blades (6) will open due to the force imposed by screwdriver bit driver and the screw to allow its passage.

The assembly of the overall system (100) can be achieved, for instance, firstly by fitting both linear motion bearings

(4) in each leg of the "U" shaped screwdriver fixing support (1) , then by fitting one end of both precision linear shafts

(5) through the motion bearings (4) . The remaining end of each linear shaft (5) is fixed in the holder (2) , particularly to the mechanical connection support A (2A) and mechanical connection support B (2B) through two screw fittings. Lastly, the centering bush (3) is attached to the holder (2) through a mechanical fitting procedure accordingly with the illustration depicted in Figure 3. Figure 4 unveils the free area in the holder (2) that will receive and promote the connection with the centering bush (3) .

In one of the preferred embodiments, the screwdriver fixing support (1) is obtained through an additive manufacturing procedure and comprises a combination of polymeric and/or metallic materials. In one of the preferred embodiments, the holder (2) is obtained through an additive manufacturing procedure and comprises a combination of polymeric materials. In one of the preferred embodiments, the centering bush (3) is obtained through a subtractive or additive manufacturing procedure and comprises a combination of metallic materials. In one of the preferred embodiments, the holder (2) and the centering bush (3) are one part, obtained by additive manufacturing and, by using part consolidation strategies .

When the automatic screw feeding and alignment system (100) is set to operate, the holder (2) will have a linear movement in ZZ plane which allows the blew screw to be fed through the pneumatic admission connection (3A) into the centering bush (3) in its lower position. At this stage, the centering bush (3) is unobstructed by the bit driver. After the screw feeding through the pneumatic admission connection (3A) , the centering bush (3) is designed to ensure the correct alignment of the screwdriver bit driver during the downward movement of the screwdriver (200) .

The procedure starts when the holder (2) is in the lower position and a screw has been blown into centering bush (3) . After the screw is on the centering blades (6) , a downward movement of the set constituted by the screwdriver fixing support (1) together with the screwdriver (200) towards the centering feature embedded in the centering bush (3) is started. Once the holder (2) meets the centering feature (3B) , it is locked in the ZZ plane. As the assembly continues its downward movement, the screwdriver fixing support (1) will approach the holder (2) , sliding on the shaft-bearing sets (4, 5) interface, until the screw bit driver meets the screw and tightens it on the product. After screwing, the set, constituted by the screwdriver fixing support (1) together with the screwdriver (200) , starts an upward movement, until the holder (2) reaches its lower position, at the shaft-bearing sets (4, 5) interface, given by a limit switch, predefined in the screwdriver software to concede the automatic functionality, thus completing a screwing cycle .

The present invention overcomes problems of the actual f eeding/screwing systems in terms of reaching a smaller deviation between the bit axis drivers of the wrench and the axis of centering bush thereby facilitating the engagement of bit driver with the screw, since it is directly attached to the screwdriver.

Claims

1. Automatic screw feeding and alignment system (100) for a screwdriver set (200) comprising a screwdriver fixing support (1) ; a centering bush (3) and a holder (2) ; characterized by the centering bush (3) being mechanically fitted to the holder (2) , and said holder (2) being adapted to the screwdriver fixing support (1) through a two shaft-bearing set comprised of linear motion bearings (4) and precision linear shafts (5) ; wherein the shaft-bearing sets ensures a uniform parallel relative movement between the screwdriver fixing support (1) and the holder (2) , and the centering bush (3) comprises protrusions configured to ensure the correct alignment of a bit driver installed in the screwdriver set (200) and a screw installed inside the centering bush (3) during the movement between the screwdriver fixing support (1) and the holder (2) .

2. Automatic screw feeding and alignment system (100) according to the previous claim, wherein the screwdriver fixing support (1) comprises a "U" shaped format adapted to fit a screwdriver set (200) through its basis and said support (1) comprises protrusions on the extremities of the "U" shaped format to promote the fitting of the linear motion bearings ( 4 ) .

3. Automatic screw feeding and alignment system (100) according to any of the previous claims, wherein the holder (2) comprises two mechanical connection supports, mechanical connection support A (2A) and mechanical connection support B (2B) , aligned with the extremities of the "U" shaped format of screwdriver fixing support (1) , adapted to mechanically secure one end of each linear shaft (5) through screw fittings .

4. Automatic screw feeding and alignment system (100) according to any of the previous claims, wherein the centering bush (3) comprises "Y" shaped format with a screwdriver admission connection (3B) , a pneumatic admission connection (3A) and an output connection, wherein the screwdriver admission connection (3B) is centred and aligned with the output connection, promoting the connection between the bit driver and the screw.

5. Automatic screw feeding and alignment system (100) according to any of the previous claims, wherein the pneumatic admission connection (3A) promotes a perpendicular admission of at least a screw in the centering bush (3) that will be further aligned with bit driver on the output connection .

6. Automatic screw feeding and alignment system (100) according to any of the previous claims, wherein the pneumatic admission connection (3A) of centering bush (3) is centrally positioned with regard to the holder (2) and to the screwdriver fixing support (1) .

7. Automatic screw feeding and alignment system (100) according to any of the previous claims, wherein the screwdriver fixing support (1) is obtained through additive manufacturing procedure and comprises a combination of polymeric and metallic materials. 16

8. Automatic screw feeding and alignment system (100) according to any of the previous claims, wherein the holder (2) is obtained through an additive manufacturing procedure and comprises a combination of polymeric materials.

9. Automatic screw feeding and alignment system (100) according to any of the previous claims, wherein the centering bush (3) is obtained through a subtractive or additive manufacturing procedure and comprises a combination of metallic materials.

10. Operating method of the automatic screw feeding and alignment system (100) for a screwdriver set (200) according to any of the previous claims 1 to 9, comprising the steps of a screw is blown through the pneumatic admission connection (3A) into the centering bush (3) ; the screw is positioned in a lower position of the centering bush (3) and will be aligned within the centering bush (3) with a bit driver of the screwdriver (200) ; the bit driver, promoted by the movement of the screwdriver set (200) mechanically connected to the screwdriver fixing support (1) , enters through the screwdriver admission connection (3B) in a linear movement towards a screwing plane, mechanically connecting with the screw, promoting the centering blades (6) to open due to the force imposed by the bit driver and the screw, allowing its passage in towards the screwing plane; after the screw being screwed to the screwing surface through the rotation movement performed by the bit driver, the holder (2) performs an opposite linear 17 movement with regard to the screwing plane , promoting the centering bush ( 3 ) to be unobstructed by the bit driver, allowing the admission of another blown screw through the pneumatic admission connection ( 3A) .