US3903334A

US3903334A - Method for capping the ends of pencils

Info

Publication number: US3903334A
Application number: US457255A
Authority: US
Inventors: Eric Reinhard
Original assignee: Fabrique Suisse de Crayons Caran dAche SA
Current assignee: Fabrique Suisse de Crayons Caran dAche SA
Priority date: 1973-04-12
Filing date: 1974-04-02
Publication date: 1975-09-02
Anticipated expiration: 1992-09-02
Also published as: FR2233160A1; JPS50925A; DE2416327A1; FR2233160B3; CH562702A5

Abstract

A method for capping the rear ends of pencils according to which a single operation is required, that is an application, preferably through steeping, of a molten thermoplastic material onto said ends. An advantageous arrangement for executing such a method consists in means loading successive rows of pencils onto a horizontal plane in a rotary carrier, said carrier revolving stepwise so as to bring the successive rows into a predetermined, preferably vertical, position in which the application of the thermoplastic material may be executed for instance by raising transiently a vat filled with such a material into engagement with the pencil ends, the material thereafter being allowed to set before the pencils enter a further position from which they are removed.

Description

United States Patent [1 1 Reinhard METHOD FOR CAPPING THE ENDS OF PENCILS [75] Inventor:

[73] Assignee: Fabrique Suisse de Crayons Caran dAche S.A., Geneva, Switzerland 221 Filed: Apr. 2, 1974 21 Appl. No.: 457,255

Eric Reinhard, Gaillard, France [58] Field of Search 117/37 R, 43, 117, 104 R, ll'7/105.3, 105.4, 160 R, 116; 118/421, 426, 429; 401/49, 98

[56] References Cited UNITED STATES PATENTS 2,355,278 8/1944 Davis 118/426 X 1 Sept. 2, 1975 2,774,398 12/1956 Morin 117/117 X Primary ExaminerThomas J. Herbert, Jr. Assistant Examiner-Bruce H. Hess Attorney, Agent, or Firm--Emory L. Groff, Jr.

[5 7 ABSTRACT A method for capping the rear ends of pencils according to which a single operation is required, that is an application, preferably through steeping, of a molten thermoplastic material onto said ends. An advantageous arrangement for executing such a method consists in means loading successive rows of pencils onto a horizontal plane in a rotary carrier, said carrier revolving stepwise so as to bring the successive rows into a predetermined, preferably vertical, position in which the'application of the thermoplastic material may be executed for instance by raising transiently a vat filled with such a material into engagement with the pencil ends, the material thereafter being allowed to set before the pencils enter a further position from which they are removed.

8 Claims, 1 Drawing Figure METHOD FOR CAPPING THE ENDS OF PENCILS The invention has for its object a method for capping or coating the rear of a pencil, that is the end opposed to the writing tip and also an arrangement for executing said method.

It is a well-known fact that the present day pencilcapping methods require several operations including, a feeding of the pencils into a machine adapted to secure them to a support and an application over the ends of the pencils of a first or primary varnish as provided by conveying the pencils through a first vat carrying said varnish, after which a second capping or ornamental varnish is applied to the pencil in a second vat.

Such methods are time-consuming since they entail between the successive operative stages drying periods following each application of varnish. Furthermore, such methods require the use of several machines lying at different locations and this means much room and handling are necessary and, consequently considerable manpower is required for the operation of stands, carriages, elevators and the like.

The present invention covers a simple capping method adapted to eliminate the above mentioned drawbacks of prior technique. This is achieved according to the invention by a single application over the rear end of the pencil of a molten thermoplastic material. The hardening or setting of said material is accomplished by a rapid cooling step, which lasts only a few seconds. The entire capping operation is thus completed within a very short time.

The thermoplastic material is applied at a temperature slightly above its melting temperature and this thermoplastic material may be applied through immersion of the pencil or through any other suitable means.

The present invention also covers an arrangement for carrying out the above-disclosed method, the novel feature of which arrangement consists in that it includes means for loading the pencils into a movable carrier and holding them in a vertical position on the latter and includes further means for applying the thermoplastic material onto the pencil ends.

The accompanying drawing illustrates, diagrammatically and by way of example, an arrangement for the execution of the improved method referred to hereinabove.

The single FIGURE of said drawing illustrates diagrammatically such an arrangement comprising an automatic machine for the capping of pencil ends at a raised temperature. Such a machine includes a loading station provided with a feed hopper l carrying the pencils to be capped. Over the flat bottom of the hopper, pusher members 2 are adapted to slide to thereby urge successive rows of pencils 3 lying on said bottom into a loading drum 4 adapted to revolve round a transverse horizontal axis. Said drum has radial slots such as 5 associated with pencil-holding means which allow the pencils to form successive radially directed rows. Said drum 4 is rotatedly driven by a motor which is not illustrated, so as to revolve stepwise in the direction of the arrow f.

The arrangement also includes means 6 ensuring an accurate alignment of the pencils in their respective rows and a steeping station 7 comprising a constant level steeping vat capable of a vertical reciprocation of an unvarrying length. The vats are of an overflow type and are controlled by a temperature regulator 8.

The arrangement still further includes pencildischarging means 9. 7

Each time the rotary drum 4 progresses by one step, the successive rows of pencils face the successive stations i.e. the loading station provided with the feed hopper l, the aligning station 6, the steeping station 7 where they are submitted in a vertical position to a hot capping operation and the discharging station or means The capping product comprises a hot-melt composition of thermoplastic resins which is caused to melt in the heated double vat forming the steeping station. The reciprocatory travel of the double vat and the level therein as defined by an overflow are constant while the excess of capping material is recovered in a large vat and recycled.

The shape of the capping and the weight of material applied depend, on the one hand, on the speed of the steeping operation and, on the other hand, on the adjustment of the temperature of the molten material.

A heating system keeps the capping hot-melt material in its fluid condition and its temperature is controlled and stabilized at the desired value by suitable means which are not illustrated. A modification in the temperature of the hot-melt changes its viscosity and consequently the amount of material applied over each pencil end.

The hot-melts require a temperature ranging between and 280C for the material which is to be considered nowadays; however, these temperatures are by no means binding and, according to their nature, a range of viscosity of 1600 to 4300 cp can be obtained for temperatures between 149 and 191C in the case of certain known products.

The cap formed over the end of the pencil may be transparent, but it is possible to incorporate a pigment with the thermoplastic material, so as to obtain a colored cap.

During the setting of the thermoplastic material, the pencil is held in a substantially vertical position so that the thermoplastic material may assume a convex shape although it is applied over the flat transverse end surface of the pencil. This improves the appearance of the pencil without it being necessary to resort to the conventional step which consists in shaping the end of the pencil in order to make it assume a convex shape.

it is not quite essential to hold the pencil in a vertical position since the surface pressure which the molten product may show can be sufficient for the end of the pencil to assume the desired convex shape when capped.

The pencils 3, which have thus been capped at a raised temperature, are discharged horizontally out of the drum at the discharging station 9 whence they drop onto a conveyor belt 10 which carries them towards a container 1 l or towards a further machine, which is not illustrated. The pencils may also be discharged through the upper part of the drum 4.

The above-disclosed hot-capping methodcan thus be executed very simply and its application is highly versatile.

The hot-steeping or capping method thus shows, over conventional methods, large and important advantages. It requires, in fact, a single operative step resorting to a single product while a single plant is used which incorporates all the operative stations corresponding to the loading, alignment, steeping and discharging steps.

This results in a substantial gain in room, time, appliances, handling and manpower required and the operation can be controlled by a single workman.

It should be noted that the capping material considerably simplifies the present method, as compared with conventional methods. The latter require, in fact, the application of two varnishes in succession with substantial drying periods after each application. The novel above-described method eliminates these drying methods.

Other advantages of the present method are, for example, the capping without any waste of material, an excellent control of the temperature which allows a uniform production to be obtained, an immediate and automatic discharge of the pencils after their steeping, a high rhythm of operation and low upkeep costs for the plant.

The example described relates to the steeping in a bath of thermoplastic material. Obviously, however, the improved method may resort as well to other techniques such, for instance, as the projection of thermoplastic material or else a molding or the like technique.

I claim:

1. A method for capping the ends of pencils opposed to their writing tips, consisting in urging the pencils bodily into a position wherein said ends lie on a common line, applying in a single stage a molten thermoplastic material onto said ends and allowing said material thus applied to set.

2. A method as claimed in claim 1, in which the temperature of the molten thermoplastic material ranges between and 300C.

3. A method as claimed in claim 1, in which the pencil ends to be capped are flat and face downwardly during the application of material whereby the shape assumed by the material applied to said ends is convex after it is set.

4. A method as claimed in claim 1, in which the position into which the pencils are urged is a vertical position with the pencil ends facing downwardly and the pencils retain said position during the setting of the material.

5. A method as claimed in claim 1, in which the application of the thermoplastic material is performed through steeping of the pencil ends in a bath of said material.

6. A method as claimed in claim 1, in which the application of the thermoplastic material is performed through projection of the molten thermoplastic material onto the pencil ends.

7. A method as claimed in claim 1, wherein the ther moplastic material is molded over the pencil ends.

8. A method as claimed in claim 1, in which coloring matter is incorporated with the molten thermoplastic material.

Claims

2. A method as claimed in claim 1, in which the temperature of the molten thermoplastic material ranges between 80* and 300*C.

7. A method as claimed in claim 1, wherein the thermoplastic material is molded over the pencil ends.