US2229398A - Foot or support for typewriting and like machines - Google Patents

Description

1941- R. G. THOMPSON 2,229,398

FOOT OR SUPPORT FOR TYPEWRITING' AND LIKE MACHINES Filed Sept. 19, 1938 Patented Jan. 21, 1941 UNITED STATES PATENT OFFICE FOOT OR SUPPORT FOR TYPEWRITING AND LIKE MACHINES Application September 19, 1938, Serial No. 230,580

3 Claims.

My invention relates to a foot or support fo1 typewriting and like machines.

One of the main objects of my invention, generally stated, is to provide improved, highly eiiicient and reliable cushion supporting means for typewriting and like machines.

Another object of my invention is to provide an improved supporting means, or foot for typewriting or like machines whereby the shock and vibrations incident to the operation of such machines may be cushioned or materially absorbed and the noise consequently materially reduced or eliminated.

A further object of my invention is to provide a foot for typewriting or like machines as specified above, which affords a stable support for such machines and which will securely grip the supporting surface to prevent lateral displacement of the machine thereon.

A still further object of my invention is to provide a supporting means or foot as specified above which is a composite or unitary structure that may be easily applied to a typewriting or like machine and which is comparatively inexpensive to manufacture.

To the above and other ends which will hereinafter appear, my invention consists in a foot of the character set forth in the following description and particularly pointed out in the appended claims.

In the drawing, wherein like reference characters designate corresponding parts in different views:

Fig. 1 is an enlarged side elevational view of one form of a foot constructed in accordance with the present invention, and shown applied to a typewriting machine represented by a fragmentary portion of a frame thereof.

Fig. 2 is an enlarged vertical sectional view taken on line 22 of Fig. 1 and viewed in the direction of the arrows at said line.

Fig. 3 is an enlarged horizontal sectional view taken on line 3-3 of Fig. 2 and viewed in the direction of the arrows at said line.

In the usual typewriting machine, there are four feet provided for supporting the machine on the surface of a desk or the like. It is assumed in the present instance that all of such feet may be alike or generally of a similar nature, and accordingly only one of such supporting feet have been shown in the drawing. In accordance with the present invention, each of the supporting feet is a composite or unitary structure including a centrally disposed metal attaching member surrounded by a flexible rubber cushion member with means provided for reinforcing the outer edge portion of the cushion member. A centrally disposed cavity is provided in the lower surface of the cushion member beneath the lower end of the attaching member to afford resilient downward movement thereof and to provide a suction grip of the foot on the supporting surface.

In the form of the present invention shown in the drawing, the attaching member is in the form of a metal screw 20 having spaced annular flanges 20 and a threaded upper end portion 20 A portion of a frame l2 of a typewriting machine is shown in Figs. 1 and 2, as provided with a tapped vertically disposed opening II in the lower surface thereof for receiving the threaded portion 20 which is turned therein until the shoulder formed by the upper flange 20' engages the lower surface of the frame I2. However, it is to be understood that means other than the threaded portion 20 may be provided for holding the attaching member 20 to the typewriter frame as may be required in the particular machine to which the feet of the present invention are to be applied.

The cushion member around the attaching member 20 in the present instance is in the form of a relatively soft rubber core member 22 moulded around and fixed to the lower end por tion of the attaching screw 20. Means are provided for affording a secure grip between the attaching member 20 and the core or cushion.

member 22. Thus in the illustrated embodiment of the present invention the rubber core 22 is moulded in the groove or intermediate portion between the flanges 20' thereby preventing any possibility of displacement of the attaching member 20 relative to the inner portion of the rubber core member 22. However, it will be understood that the lower end portion of the retaining member 20 may be of various other irregular shapes, such as a plurality of grooves therein or other forms of projections or serrations thereon to obtain substantially the same result.

The rubber core or cushion member 22 is substantially circular at its outer edge in the illustrated form, although various other shapes may be provided if desired. The rubber core 22 being comparatively soft and flexible, reinforcing means around the outer edge thereof is provided to prevent undue contraction or expansion at the outer edge portion of the cushion member 22 when downward pressure is applied to the retaining member 20, as will hereinafter appear.

Thus it is desirable that the reinforcing means be less elastic than the cushion or core member 22, and in the illustrated form of the present invention, such a reinforcing means is provided by a shell 24 of a rubber composition which is harder and less elastic than the rubber core member 22. The comparatively hard rubber shell member 24 is disposed around the outer edge of the cushion member 22 in laterally spaced relation to the retaining member 20, and in addition to the rubber shell 24, a reinforcing metal ring 25 is mouldedin the outer edge portion of the cushion member 22.

In order to ensure a firm grip of the foot on the supporting surface to prevent the machine from sliding on such surface, I prefer to provide a rubber reinforcement 26 which covers the lower surface of the cushion member 22, the shell 24 and the ring 25. This reinforcement 26 may be of the same nature of rubber composition as the reinforcing shell 24.

As previously stated the soft rubber core 122 is moulded around the portion of the attaching member between the flanges 20' so that the attaching member 20 is permanently secured thereto, and all the other rubber parts including the cushion core 22, the retaining shell 24, the reinforcing ring 25 and the bottom contact portion 26 are all vulcanized together to form a unitary integral structure surrounding anii attached to the attaching member 20.

It may be desirable to treat the lower end of the attaching member 20 and the ring 25 so that upon vulcanization of the various parts of the foot construction, the rubber composition of the cushion member 22 will adhere to the metal surface of the retaining member 20 and reinforce ing ring 25 to provide a strong bond between the metal and the rubber. However, it is believed that this special treatment of the metal retaining member 20 will not always be necessary as the flanges 20 should serve to prevent any displacement of the retaining member 20 relative to the surrounding portion of the cushion member; 22.

Referring to Fig. 2, it may be seen that a cavity 21 is formed in the central portion of the lower surface of the composite foot construction. This cavity 21 is located beneath the soft rubber core 22 and the lower end of the retaining member 20, and when the lower surface of the member 26 engages the supporting surface for the ;typewriting machine, it will be clear that the 'lower end of the retaining member 20 is resiliently supported in upwardly spaced relation to such supporting surface. It will accordingly be apparent that the weight of the typewriting machine can effect a slight extent of vertical or axial displacement of the attaching member 20 with relation to the supporting surface due to the clasticity of the cushion member 22.

It also will be apparent that this resilient displacement of the attaching member 20 relative to the supporting surface will be afforded more particularly by a tensioning action in the soft rubber cushion member 22 rather than a compressing action thereof. In other words, a downward pressure on the attaching member 20 causes substantially a stretching action of the rubber cushion member 22, such stretching action taking place between the inner portion of thecushion member 22 which is firmly held by the attaching member 20 and the outer edge portion of the cushion member which is vulcanized to the inner surface of the reinforcing shell 24 and ring 25. The ring 25 and shell 24 prevent any contraction or expansion of this outer edge portion of the cushion member.

The yieldable rubber contact member 26 around the outer portion of the lower surface of the foot construction affords a substantially air-tight seal upon any smooth supporting surface for the typewriting machine, and the upper walls of the cavity 21 are hermetically sealed. Thus, a suction gripping action of the foot upon the supporting surface will result after any downward displacement of the attaching member 20 relative to the supporting surface caused by the weight of the typewriting machine. This suction gripping action of the present foot construction serves to very effectively prevent any accidental or unwarranted upward or lateral shifting of the typewriting machine upon its supporting surface. It will further be clear that the present foot construction which affords slight axial displacement of the attaching member 20 relative to the supporting surface for the machine, will permit this suction gripping action regardless of any slight variation in the plane of the supporting surface relative to the typewriting machine.

In the illustrated form of the present invention, the outer surface of the reinforcing member for the outer edge of the rubber cushion member is of rubber composition joined by vulcanization to the cushion member, thereby providing a uniform smooth outer surface throughout the foot construction. In this manner, a. foot having a very attractive appearance is provided in a Very inexpensive manner as the use of enameled or plated parts is not required. In the form of the present invention illustrated in the drawing, a transverse screw driver slot is shown in the lower endof "the attaching member 20 to facilitate the assembly of the foot construction on the typewriting machine.

It will be seen that I have thus provided a very simple and highly effective unitary foot construction for typewriting and like machines. The use of composite rubber parts in the present foot construction having different degrees of hardness and flexibility affords the very desirable result of providing a stable supporting means for a typewriting and like machine which at the same time has sufiicient cushioning action to absorb the shock or vibration incident to the operation of such machine, and thus reduce or eliminate the noise that ordinarily results therefrom.

Anotherv important feature of the present invention is the construction wherein the rubber cushion is substantially in tension'rather than compression as in the usual form of rubber feet. This feature greatly increases the effective life of the foot as the resilient cushioning properties of the rubber under tension can be maintained for a much longer period of time than when the rubber is being compressed by the weight of the machine between two rigid members as in the usual construction.

A further feature of the present invention is the provision of a supporting foot which is moulded and vulcanized into a unitary construction wherein there are no exposed metal parts requiring a finishing operation such as plating or enameling. The moulding or vulcanizing of the metal and rubber parts of present foot into a unitary construction is a feature which also permits an eifective vacuum or suction grip to be maintained, as the entire wall of the cavity in the lower surface thereof is hermetically sealed. In ordinary foot constructions having a retaining screw or the like which is detachable from the other Ill parts of the foot, the walls of the space beneath the lower end of such detachable screw are not hermetically sealed and accordingly an effective vacuum cannot be maintained.

It will be observed, moreover, that the metal screw 20 is firmly attached to the frame of the machine and that there are no other metal to metal contacts between the foot and frame; the rubber of the foot constituting an insulation between such metal parts and the support for the machine and between the screw 20 and the metal ring 25 thereby effectively supporting the machine against the transmission of vibrations from. the machine to the desk or support therefor.

Various changes may be made in the construction, and certain features thereof may be omitted without departing from my invention as it is defined in the accompanying claims.

What I claim as new and desire to secure by Letters Patent is:

1. In a foot for typewriting and like machines, the combination of an attaching member, a flexible rubber cushion surrounding an end portion of said attaching member, and means for reinforcing the outer edge of said cushion comprising a rigid ring embedded in the outer edge portion of the cushion member, and a shell of harder rubber than the cushion surrounding said ring and bonded to the cushion.

2. In a foot for typewriting and like machines, the combination of an attaching member having a grooved end portion, a flexible rubber cushion extending laterally from said groove of the attaching member, and means for reinforcing the outer edge of said cushion comprising a shell of harder rubber than the cushion and vulcanized to the edge and bottom portion of the cushion to form a cavity beneath the lower end of said attaching member.

3. In a foot for typewriting and like machines, a vertically disposed metal attaching member, a metal ring spaced laterally around said attaching member, a flexible rubber cushion vulcanized to said attachi..g member and to said ring, and a shell of harder rubber than said cushion vulcanized to said ring and to said cushion.

RUSSELL G. THOMPSON.

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