GB2036187A

GB2036187A - Hand held desoldering instrument

Info

Publication number: GB2036187A
Application number: GB7937996A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1978-11-09
Filing date: 1979-11-02
Publication date: 1980-06-25
Also published as: JPS5568176A; CA1129258A; FR2440805B1; FR2440805A1; GB2036187B; DE2942701C3; DE2942701A1; DE2942701B2

Abstract

A hand held desoldering instrument comprises a cylindrical barrel 10 which forms an internal solder retaining chamber. The front end consists of a tip assembly including an end cap 15 and a nozzle tip 16, both being connected to the barrel by an adaptor ring (17) threadably connected to the barrel. A housing 30 is secured by threads to the rear end of the barrel and includes a hollow chamber disposed laterally adjacent to the longitudinal axis of the barrel for housing a spring. A hand operable cap 23 extends into the hollow chamber for compressing the spring. A rod 22 interconnects the hand operable cap to a piston slidable in the barrel, terminating in a cleaning tip for cleaning the nozzle tip. The rod for operating the piston is provided with a recess cooperating with a pushbutton 33 for releasably locking the rod. Alternatively a lever 60 may be secured to the opposite end of the pushbutton to permit release of the cocked instrument from the opposite side of the barrel. <IMAGE>

Description

SPECIFICATION Hand held desoldering instrument This instrument relates generally to desoldering instruments and particularly relates to an instrument of the type which is hand held and where the vacuum is created by a piston.

The desoldering instrument of the invention may be considered to be an improvement of the portable desoldering tool disclosed and claimed in the Applicant's prior patent 3,912,149. Desoldering instruments are generally used in the electrical arts to desolder an electrical connection. In this case the solder first has to be heated to melt the solder.

Thereafter, the solder should be removed before it has an opportunity to harden again and without spattering or dropping the solder or flux onto the electrical circuit.

To this end non-portable central vacuum systems have been devised in the past. Also relatively small hand held efficient vacuum stoke tools have been developed in the past, an example of which is the Applicant's prior patent.

In order to reduce the flyback or kickback of the instrument it is highly desirable to make the piston and the other parts associated with its motion as light as possible without sacrificing its efficient vacuum action.

It is accordingly an object of the present invention to provide a small, compact, hand held desoldering instrument which efficiently creates a high vacuum for drawing in solder or other materials.

Briefly these objects are achieved in accordance with the structural aspects of an embodiment of the invention in which a desoldering instrument comprises a cylindrical barrel which forms an internal ssolder retaining chamber and is otherwise free of the cocking spring. One end of the barrel is closed by a tip assembly including an end cap and a nozzle tip. The the end cap and noozzle tip may be constructed in accordance with the Applicant's prior application Serial No.

922,676 of July 7, 1978. However, other end caps and nozzle tips may be used instead.

The tip assembly further includes an adaptor ring having means for retaining the end cap and having a threaded connection with the barrel.

A piston cocking shaft or rod extends into the barrel and carries a piston and a cleaning rod forwardly thereof for cleaning the nozzle tip during each cocking cycle. A housing is threadably connected to the rearward end of the barrel and includes a portion laterally adjacent to the longitudinal axis of the barrel and forms a hollow chamber for housing the cocking spring. A hand operated cap is secured to the piston cocking shaft and has a depending portion bearing against the spring in the hollow chamber. To this end the hollow chamber is slotted along its length to permit the cap to pass therethrough.

The piston cocking shaft is provided with a latching recess which may be releasably retained by a spring biased trigger button extending transversely through the housing and slidable therein. The trigger button has means thereon such, for example, as a pin for releasably engaging the recess on the piston cocking shaft. The shaft is released by disengaging the pin from the recess by pushing on the button against its biasing spring.

Alternatively, the button may be hooked to a lever extending substantially along and toward the tip end of the barrel for moving the trigger button to release the piston cocking shaft.

The present invention is a hand-held desoldering instrument comprising a cylindrical barrel forming an internal solder-retaining chamber, a tip assembly including an end cap and a nozzle tip, said tip assembly further including an adaptor ring having means for retaining said end cap and nozzle tip and further having means for connecting it to said barrel at its forward end, an elongated rod-like member including a nozzle tip cleaning rod carried on its forward end, said elongated member having a recess therein, a piston secured to said elongated member, a housing having means for securing it to the rearward end of said barrel, spring means, said housing including a portion laterally adjacent to the longitudinal axis of said barrel and forming a hollow chamber for housing said spring means, a hand-operable cap, said elongated member being secured to said cap, said cap having a depending portion bearing against said spring means in said hollow chamber, said hollow chamber being slotted along its length to permit said cap to pass therethrough; a trigger button carried by and extending transversely through said housing and slidable therein, further spring means for urging said button toward said recess, and said button having latching means thereon for releasably engaging said recess when said instrument is cocked by pushing said elongated member into said barrel, whereby said instrument can be actuated by moving said button away from said recess.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a side elevatitjnal view of the desoldering instrument of the present invention; Figure 2 is an exploded view of the barrel of the instrument of Fig. 1, the tip assembly, the piston cocking shaft and the hand operable cap but without the housing; Figure 3 is an exploded view of the housing illustrating its trigger button and spring means, the main cocking spring and the hand operable cap; Figure 4 is an end view of the end cap shown in Fig. 3; Figure 5 is a sectional veiw taken on line 5-5 of Fig. 3; Figure 6 is an elevational view similar to that of Fig. 1 Lut showing the piston in its barrel and the spring in its housing; and Figure 7 is an elevational view of the trigger button of the instrument showing a modified means for releasably locking the recess in the piston operated shaft to be used with a relatively soft metal such as aluminum.

With specific reference to Figs. 1-6 in detail it is stressed that the particulars shown are by way of example only and for purposes of illustrative discussion. Thus the instrument includes a cylindrical barrel 10 being internally threaded at both ends as shown at 11 and 12. A tip assembly 14 consists of an end cap 15 and a nozzle tip 16, both of which may be constructed as disclosed and claimed in the Applicant's prior application above referred to. The nozzle tip 16 may have a cylindrical bore. Alternatively the bore of the nozzle tip may be outwardly tapered to facilitate removal of solder by a cleaning tip in the barrel 10 as will be subsequently explained.

The end cap 15 and nozzle tip 16 are connected to the barrel 10 by an adaptor ring 17 which may have a knurled outer portion 18.

The end cap 15 may have a snap connection with the adaptor ring 17. Its rearward portion 20 is externally threaded for cooperation with the internal threads 11 of the barrel 10. In order to reduce its weight the adaptor ring 17 may be provided with one or more cutouts 21.

Preferably, the end cap 15 and nozzle tip 16 consist of electrically conductive material such as a plastic material having incorporated therein conductive particles. By way of example, the nozzle tip 16 may consist of polytetrafluoroethylene. The end cap 15 may consist of a similar material both being heat resistant and electrically conductive, that is of low electric resistance to avoid the buildup of large electrical charges on delicate integrated circuits and the like. These electrical charges are created by the desoldering instrument and may be caused, for example, by the sliding contact between the O-ring 26 of the piston and the lubricant in the barrel 10. Preferably the end cap and nozzle tip of the Applicant' s prior application above referred to are also made of electrically conductive material of the type discussed herein.

A piston cocking shaft 22 is connected to an end cap 23 which is hand operable for cocking the instrument. The piston cocking shaft 22 is provided with an annular recess 24 for locking it in a cocking position as will be more fully explained hereinafter. The shaft 22 also carries a piston 25 which may be provided with an O-ring 26 for sealing it to the internal wall of the barrel 10. The shaft 22 may be provided with a plurality of spaced markers 27 for controlling the permissible motion of the piston 25 as willl be more fully explained hereinafter. The piston 25 may be threadably connected to the shaft 22. The outer end of the coding shaft 22 is provided with a smaller diameter pin 28 serving as a nozzle cleaning pin.

A housing 30 is provided which preferably consists of a plastic material which is selflubricating, which may readily be molded and which has structural integrity, that is dimensional stability. Such a plastic is acetal resin which is known under the trademark Delrin.

The housing 30 has a relatively wide transverse opening 31 extending therethrough and terminating in an opening 32 of much reduced diameter. Disposed in the opening 31 is a trigger button 33. The trigger button 33 is shown in Fig. 3 rotated through 90 to better illustrate its construction. It has an elongated opening 34 extending therethrough through which a latching pin 35 extends. The end portion 36 of the trigger button 33 is flat as shown at 37 and ends in a disk 38. A trigger button spring 40 is provided which bears against a shoulder 41 of the trigger button 33. The other end of the spring 40 rests against a shoulder 39 formed between the openings 31 and 32. The trigger button 33 and the spring 40 are inserted into the opening 31 until the button 38 extends through the housing 30.The piston carrying shaft 22 extends through the opening 34 and hence retains the trigger button.

The housing 30 contains a main spring holder 43 having an axis parallel to the central axis of the barrel 10. In other words, the hollow chamber has a portion 43 disposed laterally adjacent to the barrel 10. It houses a cocking spring 45, one end of which bears against a shoulder 46 adjacent the opening 31 for the trigger button 33. The other end of the cocking spring 45 bears against a depending portion 47 of the hand operable cap 23.

The dependent portion 47 is substantially circular and capable of extending through the cylindrical space 48 in the holder 43 which contains the spring 45. The cylindrical chamber 48 is slotted as clearly shown at 50 in Fig. 5 to permit the dependent portion 47 with its narrow connection 51 to pass therethrough. Also shown in Fig. 5 is a central opening 52 having an axis coinciding with the central axis of the barrel 10 for the piston coccking shaft 22 to pass through.

The operation of the instrument of the invention will now be apparent. The instrument may be cocked by pushing the finger against the curved surface 54 of the end cap 23 until the pin 35 of the trigger button 33 engages the annular recess 24 in the cocking shaft 22.

The trigger button is pressed by its spring 40 with its pin 35 against the recess 24. The instrument may be released to create a vacuum by pushing on the trigger button 33.

This will release the shaft 22 and permit the piston 25 to fly back thus creating a vacuum in the barrel forwardly of the piston.

Alternatively, the instrument may be cocked by pushing an external cocking rod such as a pencil or the like against the depending portion 47 of the cap 23. This may also be effected by a suitable bench mounted mechanism as while holding the instrument in an upright position and pushing down with a lever or the like onto the dependent portion 47.

The instrument may be assembled as follows. The cocking spring 45 is introduced into its chamber 48. Now the bias spring 40 and pushbutton 33 are pushed into the opening 31 in such a manner that the opening 34 in the pushbutton faces the piston cocking shaft 22. Thereupon the cocking shaft 22 is introduced into the opening 52 while a dependent portion 47 pushes against the end of the cocking spring. Now the piston 25 is screwed onto the shaft 22. The housing 36 is then screwed onto the barrel 10 by its external threads 55 as well as the adaptor ring 17 with its end cap 15 and nozzle tip 16 out the barrel through 11. The instrument is now ready to be used.

As shown in Fig. 1, it is also feasible to trigger the instrument by a lever 60 which extends along the barrel 10. The lever 60 has two fingers 61, each ending in an upturned portion 62. This lever may be pushed through the narrow portion 37 below the button 33.

By depressing the outer end of the lever 60 the two fingers 61 will tilt over a flat surface 63 of the housing 30, thereby to move the trigger button 33 inwardly to release the shaft 22.

However, it will be understood that the lever 60 is optional and may be omitted if desired. It has, however, the advantage that it permits to trigger the instrument adjacent and along the barrel 10 rather than beyond the rear end of the barrel 10.

The markings 27 on the shaft 22 serve the purpose to show that the stroke of the instrument has been reduced. This may simply be effected by putting a suitable ring such as a rubber ring over the shaft 22 adjacent the piston 25. One or more such spacer rings may be introduced into the barrel 10 to limit the stroke where desired. In other words the rapid return stroke of the piston 25 is thus reduced where the full stroke is not needed.

It will be noted that the barrel 10 is entirely free of the cocking spring 45. The spring 45 in turn is disposed adjacent the barrel, that is spaced from its central axis and along the housing 30.

To emphasize again, the instrument may be cocked either by pushing with the finger on the surface 54 by pushing a rod such as a pencil through the opening 48 or by some mechanical means. Further, the instrument may be released by either pressing on the trigger button 33 or depressing the lever 60 as shown in Fig. 1.

The construction shown so far is suitable when the rod 22 consists of steel which will not be worn out by a steel member such as the latching pin 35. However, in order to save weight it may be desirable to manufacture the rod 22 of aluminum which may be worn down or eventually damaged by a steel pin 35 cooperating with the recess 24. Therefore the construction of Fig. 7 may be used instead. Here the button 33 shown rotated through 90 with respect to the showing in Fig. 3 is provided along its reduced portion 36 with a slot 65 which is rearwardly slanted.

A brass coated lead disk 66 may be inserted into the slot 65 to cooperate with the recess 24 on an aluminum rod 22.

There has thus been disclosed a hand held desoldering instrument. The instrument features a light weight plastic main body or housing in which is located the cocking spring. A push button has means for locking the piston cocking shaft on a recess thereof.

The release button is spring biased and may be depressed to release the instrument. Alternatively, the instrument may be operated by a lever extending adjacent the barrel of the instrument. The instrument may alternatively be cocked by pushing down on a substantially circular dependent portion of the hand operable cap which in turn depresses the cocking spring.

Claims

1. A hand held desoldering instrument comprising a cylindrical barrel forming an internal solder-retaining chamber, a tip assembly including an end cap and a nozzle tip, said tip assembly further including an adaptor ring having means for retaining said end cap and nozzle tip and further having means for connecting it to said barrel at its forward end, an elongated rod-like member including a nozzle tip cleaning rod carried on its forward end, said elongated member having a recess therein, a piston secured to said elongated member, a housing having means for securing it to the rearward end of said barrel, spring means, said housing including a portion laterally adjacent to the longitudinal axis of said barrel and forming a hollow chamber for housing said spring means, a hand-operable cap, said elongated member being secured to said cap, said cap having a depending portion bearing against said spring means in said hollow chamber, said hollow chamber being slotted along its length to permit said cap to pass therethrough, a trigger button carried by and extending transversely through said housing and slidable therein, further spring means for urging said button toward said recess, and said button having latching means thereon for releasably engaging said recess when said instrument is cocked by pushing said elongated member into said barrel, whereby said instrument can be actuated by moving said button away from said recess.

2. An instrument as claimed in claim 1, wherein said housing and cap consist of a self-lubricating plastic having substantially structural integrity.

3. An instrument as claimed in claim 1 or claim 2, wherein said elongated member consists of steel.

4. An instrument as claimed in any preceding claim, wherein said means on said button consists of a pin for releasably engaging said recess.

5. An instrument as claimed in claim 1 or claim 2, wherein said elongated member consists of aluminum.

6. An instrument as claimed in claim 5, wherein said means on said button includes a slot therein and a brass coated lead member for releasably engaging said recess.

7. An instrument as claimed in claim 1, wherein said adaptor ring consists of aluminum.

8. An instrument as claimed in claim 7, wherein said adaptor ring is provided with cutouts to reduce its weight.

9. An instrument as claimed in any preceding claim, wherein a lever is provided extending forwardly along said barrel and disposed opposite said button, said lever having means for engaging the adjacent end of said button, thereby to releasably engage said recess.

10. An instrument as claimed in claim 9, wherein said lever is provided with two spaced fingers, each ending in an upturned portion, while the end of said button is provided with a reduced portion terminating in a disk for engaging said fingers.

11. An instrument as claimed in any preceding claim, wherein said hollow chamber is rearwardly open to permit compressing of said spring means from the outside.

12. A hand held desoldering instrument substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.