US3889472A - Reciprocating apparatus - Google Patents

Abstract

The apparatus comprises a carriage 3 moved to and fro alternately along a traverse 1 and which has two opposed resilient gudgeon pins 19 and 22. Each end of the traverse 1 carried a jack 33, 331 with the rods 37, 371 of which project inwardly. The carriage carries spindles 27, 271 resiliently mounted and each of which operates extensions 42, 421 of a slide valve of a distributor 34, 341 controlling the operation of the jacks 33, 331. When the spindle 27 comes against the extension 42 the distributor 34 is operated and causes the advance of the piston rod 37 which drives the carriage 3 back. When the latter arrives at the other end of the traverse the jack 331 reverses the drive. The apparatus is particularly applicable for paint spraying on surfaces.

Description

United States Patent [191 Guillaud 1 RECIPROCATING APPARATUS [75] inventor: Michel Guillaud, Grenoble, France [73] Assignee: Secmer, S.A., lsere, France [22] Filed: June 18, 1973 [211 App]. No.: 370,639

1 June 17, 1975 3,796,184 3/1973 Howkins 118/323 Primary ExaminerPaul E. Maslousky Attorney, Agent, or Firm--Dowe1l and Dowell 5 7 ABSTRACT The apparatus comprises acarriage 3 moved to and fro alternately along atraverse 1 and which has two opposedresilient gudgeon pins 19 and 22. Each end of thetraverse 1 carried ajack 33, 33' with therods 37, 37 of which project inwardly, The carriage carriesspindles 27, 27 resiliently mounted and each of which operatesextensions 42, 42 of a slide valve of adistributor 34, 34 controlling the operation of thejacks 33, 33 When thespindle 27 comes against theextension 42 thedistributor 34 is operated and causes the advance of thepiston rod 37 which drives thecarriage 3 back. When the latter arrives at the other end of the traverse the jack 33' reverses the drive. The apparatus is particularly applicable for paint spraying on surfaces.

6 Claims, 5 Drawing Figures /////////////////////////////////////////////n/&

RECIPROCATING APPARATUS The present invention relates to improvements in reciprocating apparatus. that is to say. intended to permit the to and fro displacement of a member along a slide this displacement being effected generally in a transverse manner with regard to the geometrical axis of a machine.

The known devices of the kind in question are generally realized by means of a shaft grooved by at least two contrary helicoidal peripheral grooves and on which is engaged a nut connected to the member which it is desired to displace to and fro along the bar. This latter is actuated by a unidirectional movement of rotation and the nut carries a catch which cooperates with one of the helicoidal grooves of the shaft so that this nut is given a to and fro linear movement. At the end of the bar the catch changes the groove automatically so that its movement is reversed after each traverse.

It can be easily seen that reciprocating apparatus can be obtained by utilising other well known mechanical elements such as chains, belts and the like.

The known reciprocating devices have drawbacks resulting from their complexity or from their high cost price. In any case they comprise electrical contacts which only permit with difficulty their use in an explosive atmosphere.

The improvements which form the subject of the present invention aim at remedying the above mentioned drawbacks and permitting the realization of an anti-deflagrating sliding device which is of simple and economic realization.

The reciprocating device according to the invention of the kind comprising a tool carrying carriage reciprocating to and fro along a slide. characterised in that the aforementioned slide is provided with two percussion mechanisms disposed one at each of its ends and which act in turn on one of two gudgeon pins resiliently and slidably on mounted with the carriage to reverse the direction of travel of the carriage at the extreme position selected for the end of its run in each direction.

According to one preferred embodiment each percussion mechanism is constituted by a compressed air jack controlled by a distributor the control lever of which is operated by a boss resiliently mounted on the carriage. The gudgeon pins of the carriage are preferably disposed co-axially and they are each thrust in the direction of the corresponding jack by means of a single compression spring placed between the gudgeon pins.

The invention will be described with reference to the accompanying drawings by way of example, to permit better understanding of the invention, the features which it has and the advantage which it is capable of providing:

FIG. 1 is a side elevation of an apparatus according to the invention;

FIG. 2 is an enlarged cross section on line II-II (FIG.

FIGS. 3 and 4 are detail elevations to a larger scale showing the operation of the reversing of the direction of the carriage of the apparatus;

FIG. 5 shows diagrammatically to a smaller scale the curve traced by a stylus carried by a carriage on a band running at constant speed at right angles to the direction of movement of the stylus.

There is shown in FIG. I an apparatus according to the invention cooperating with atraverse 1 associated with two vertical uprights resting on the ground on theirlower ends 20. Thetraverse 1 may be placed at any height whatever along theuprights 2 with the aid of means. not shown.

The aforementioned apparatus comprises acarriage 3 travelling to and fro alternately along the traverse l and twodirection reversing mechanisms 4, 4'.

The traverse l is made in the form of a U-shaped girder (FIG. 2) the web of which is disposed vertically. Each of the flanges of this traverse carries arail 5, 5 having in cross-section the form of a rectangle the lower face of which is grooved by a V groove 6, 6'. The tworails 5 and 5' are situated in two vertical planes offset in respect of one another theupper rail 5 being fixed nearer thetraverse 1 than thelower rail 5.

Thecarriage 3 has a general cylindrical shape and it is provided with twoarms 7, 7' extending parallel to therails 5 and 5' withbearings 8 carried by thearms 7, 7' the balls of which engage the grooves 6 and 6' in therails 5, 5'. Thecarriage 3 may comprise any tool carrier but in the present example it carries a gun 9 (FIG. 1) projecting therefrom and capable of directing paint or any other product onto asupport 10 which passes at right angles to the direction of travel of the traverse l resting on abase 11.

Thebody 12 of thecarriage 2 has anaxial bore 13 the geometrical axis of which is arranged parallel to that of therails 5, 5'. Thisbore 13 is stepped at each end of thebody 12 to constitute twoend bores 14 of greater diameter. The bores I3 and 14 thus define twoshoulders 15 against each of which is supported anannular washer 16 made of anti-deflecting material and resistant to compression. Each of these washers is held in place by means of a split pin or circlip l8 engaging in agroove 14a of eachbore 14. Agudgeon pin 19 engages in the grooves ofa stuffing box I7 and thewasher 16 extending to one of the ends of thebody 12. The inner part of this gudgeon pin is provided with aperipheral collar 20 and anaxial shank 21.

Anothergudgeon pin 22 engages in the bores of thestuffing box 17 and thewasher 16 located at the end of thebody 12 opposite to that which receives thegudgeon pin 19. Thegudgeon pin 22 is provided with aperipheral collar 23 arranged inside thebore 13 and integral with asleeve 24 incorporating anannular ring 25 into which enters theshank 21 of thegudgeon pin 19. Between thecollars 20 and 23 and co-axial with the twogudgeon pins 19 and 23 there is mounted acompression spring 26.

The construction is such that thegudgeon pins 19 and 22 project to an equal length from each end of thebody 12 of thecarriage 3.

Thecarriage 3 is provided with twocylinders 27 and 27' having the same geometrical axis arranged parallel to that of thebore 13. These twoblind cylinders 27 and 27' are open in the same direction respectively as thegudgeon pins 19 and 22, that is to say, in opposite directions. On the inside of eachcylinder 27, 27' is mounted apiston 28, 28' integral with aspindle 29, 29' the free end of which is terminated by aboss 30, 30'. Eachspindle 29, 29' passes through the open end of the corresponding cylinder through the bore of anappropriate stuffing box 31, 31'. Acompression spring 32, 32' is mounted in eachcylinder 27, 27' the ends of which are supported against, on the one hand the ends of these cylinders and on the other hand thecorresponding piston 28, 28'.

Each ofthemechanisms 4, 4 is constituted by ajack 33, 33' connected to adistributor 34, 34' (FIG. 1).

The jack 33 (FIGS. 3 and 4) comprises acylinder 35 in which is axially mounted apiston 36 therod 37 of which passes out of this cylinder and in the direction of thecarriage 3. Thisjack 33 is of the double action type. that is to say. the compressed air is sent alternately to the front of thepiston 36 through thepiping 38 to cause this latter to recede and to the rear of this piston by means of thepiping 39 to cause it to advance. Thedistributor 34 to which are connected thepipings 38 and 39 directs the compressed air coming from apiping 40 towards one or other of the aforementioned pipings by means ofaslide valve 41 which has anextension 42 directed in line with thespindle 29 of thecarriage 3.

Thecarriage 3 has a boss 43 (FIG. 1) with its axis parallel to that of thebore 13 of thebody 12 and the blind bore of which, not shown. is open in the direction to the right in the FIG. 1. This bore is connected to a source of compressed air by means of a stop valve.

The operation is as follows:

Thecarriage 3 being in any position between the twomechanisms 4, 4, the valve which controls the arrival of compressed air into the bore of thebore 43 is opened. The air escaping through the opening of this bore displaces thecarriage 3 in the direction to the left according to the principle of equality of action and reaction.

When the carriage arrives in the proximity of themechanism 4 the valve is closed again so that the carriage continues to run by inertia (FIG. 3). At the precise moment when theboss 30 comes into contact with the end of theextension 42 of thevalve 41 the end of thegudgeon pin 19 is at such a distance from the free end of thepiston rod 37 of thejack 33 that when the slide valve 4] has travelled its whole run, thegudgeon pin 19 and thepiston rod 37 are practically in contact. At this moment the compressed air arrives through thepiping 39 and thepiston 36 of thejack 33 is strongly actuated in the direction to the right (FIG. 4). This impulse is absorbed partly by thespring 26 the residual force serving to give the carriage 3 a movement from left to right. The piston rod 37' of the jack 33' of themechanism 4 is at this moment retracted due to the fact that air is driven through the piping 38 by movement of thepiston 36 to the right in thejack 33 and is directed into thejack 33 so as to cause its piston 36' to retract. When thecarriage 3 arrives adjacent to the mechanism 4' the same movements are produced as those described with reference to FIGS. 3 to 4 so that the direction of movement of the carriage is reversed.

A reciprocating device is thus realized the speed of displacement of which is constant over the whole length of its course as follows from the diagram of FIG. 5. In fact each advance and each return of a stylus carried by thecarriage 3 and resting on a sheet of paper which passes at constant speed in the direction of the arrow F is a straight line.

It is obvious that the course of thecarriage 3 which is particularly precise may be easily regulated by displacing themechanisms 4, 4' along the traverse l by means, not shown, and the speed of the carriage may be varied by varying the compressed air pressure. Of course the characteristics of thespring 26 are only valid for a certain range of variation of speeds; if the speed increases or decreased beyond the limit of this range the characteristics of this spring must be changed. The speed may moreover be raised to high levels. that is to say, it may reach a value of about three metres per second without any shock being observable at the moment of reversal of the direction of displacement.

One could furthermore if it were necessary reduce the speed of the carriage at the end of the run by fixing thejacks 33, 33' by means of rubber blocks.

It will be noted finally that thesprings 32 prevent any deterioration of thedistributor 34 or of thespindle 29 in case of any malfunction of the normal working of the change of direction. for example, at the time ofa severe lack of compressed air.

It must furthermore be understood that the preceding description has been given only by way of example and that it in no way limits the scope of the invention.

What I claim is:

1. Apparatus for reciprocating a carriage which is mounted to move freely to and fro between two extreme positions upon a traverse girder. said apparatus comprising:

a. a source of fluid under pressure;

b. on the girder at each of said extreme positions a fluid impulse mechanism operative to deliver thrust to said carriage when it reaches the extreme position to cause it to travel by inertia to the opposite extreme position; and valve means coupled between said source and each impulse mechanism and operative when actuated to deliver fluid pressure to the impulse mechanism;

c. on said carriage arm means located to actuate the valve means when the carriage reaches each of said extreme positions thereby to pressurize the adjacent impulse mechanism, and said carriage com prising a body having a bore extending therethrough and aligned with said fluid impulse mechanism, a pair of axially aligned gudgeon pins extending from both sides of the body and reciprocably captivated in the bore and disposed respectively to receive the thrust from one of said impulse mechanisms, and spring means in the bore urging the pins outwardly thereof, whereby the pins cushion the impact of the impulse mechanisms.

2. Apparatus as set forth in claim I, wherein each of said impulse mechanisms comprises a jack having a piston member extended in the direction of the carriage when the jack is pressurized.

3. Apparatus as set forth inclaim 2, wherein each jack comprises a double acting fluid pressure piston, each valve means being connected to enter fluid pressure into a space behind the piston of the corresponding jack to advance it toward the carriage, and the jacks having fluid spaces in front of their pistons which spaces are mutually connected together so that one piston is retracted when the other is advanced.

4. Apparatus as set forth inclaim 1, wherein said arm means on the carriage comprise oppositely facing spindles located to abut a valve means when the carriage reaches an extreme position and thereby actuate it to pressurize the corresponding impulse mechanism.

5. Apparatus as set forth inclaim 4, wherein each of said spindles is reciprocably mounted in a bore in the carriage and spring loaded to urge it in the direction of the valve means which it must actuate.

6. Apparatus as set forth inclaim 1, including a compressed air nozzle on the carriage and facing in one direction of travel thereof and pressurizable to displace the carriage toward the opposite impulse mechanism to initially start the movement thereof.

Claims (6)

1. Apparatus for reciprocating a carriage which is mounted to move freely to and fro between two extreme positions upon a traverse girder, said apparatus comprising: a. a source of fluid under pressure; b. on the girder at each of said extreme positions a fluid impulse mechanism operative to deliver thrust to said carriage when it reaches the extreme position to cause it to travel by inertia to the opposite extreme position; and valve means coupled between said source and each impulse mechanism and operative when actuated to deliver fluid pressure to the impulse mechanism; c. on said carriage arm means located to actuate the valve means when the carriage reaches each of said extreme positions thereby to pressurize the adjacent impulse mechanism, and said carriage comprising a body having a bore extending therethrough and aligned with said fluid impulse mechanism, a pair of axially aligned gudgeon pins extending from both sides of the body and reciprocably captivated in the bore and disposed respectively to receive the thrust from one of said impulse mechanisms, and spring means in the bore urging the pins outwardly thereof, whereby the pins cushion the impact of the impulse mechanisms.

2. Apparatus as set forth in claim 1, wherein each of said impulse mechanisms comprises a jack having a piston member extended in the direction of the carriage when the jack is pressurized.

3. Apparatus as set forth in claim 2, wherein each jack comprises a double acting fluid pressure piston, each valve means being connected to enter fluid pressure into a space behind the piston of the corresponding jack to advance it toward the carriage, and the jacks having fluid spaces in front of their pistons which spaces are mutually connected together so that one piston is retracted when the other is advanced.

4. Apparatus as set forth in claim 1, wherein said arm means on the carriage comprise oppositely facing spindles located to abut a valve means when the carriage reaches an extreme position and thereby actuate it to pressurize the corresponding impulse mechanism.

5. Apparatus as set forth in claim 4, wherein each of said spindles is reciprocably mounted in a bore in the carriage and spring loaded to urge it in the direction of the valve means which it must actuate.

6. Apparatus as set forth in claim 1, including a compressed air nozzle on the carriage and facing in one direction of travel thereof and pressurizable to displace the carriage toward the opposite impulse mechanism to initially start the movement thereof.

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