Face Shield Mounting Structure

Abstract

A face shield attached to an arcuate frame adapted for being mounted on a protective helmet in which the structure for attaching the face shield to the arcuate frame includes a rotatable cam member disposed in the region of each end of the arcuate frame. The face shield member contains slots cooperatively shaped for engagement with the cam members. Rotation of the cams within the slots of the face shield member locks the face shield to the frame.

Description

This invention relates to protective helmets having face shields mounted thereon. More particularly, the invention relates to improved structure for mounting the face shield onto a frame which is in turn adapted to be attached to the protective helmet.

Protective helmets having face shields mounted thereon are well known in the art. Typically, in the prior art a transparent face shield has been attached to a supporting frame with snap fasteners and the like. The present invention provides an improved structure for attaching the face shield member to the supporting frame as well as a novel face shield member suitable for use in combination with such an attaching structure. In brief, the present apparatus for mounting a face shield on a protective helmet is useful in combination with an arcuate (or equivalent shape) frame having a surface for contacting the top margin of a face shield member. Included with the frame are means for attaching the frame to a protective helmet. In the region of each end of the arcuate frame, face shield retainer means are provided each of which includes a cam member rotatably mounted on the frame surface. Means are connected for rotating each of said cam members. Each cam member extends above the frame surface so that engagement can be accomplished with a cooperatively shaped slot in the top margin of a face shield member. Rotation of the cams within the slots against the edges thereof serves to lock the face shield to the frame.

The structure of this invention provides a more secure and positive mounting of the face shield onto the supporting frame. Previously used techniques are subject to dislodgement by unintended impact for example so that the protective nature of the device may be impaired at least under certain circumstances. The present manner of attaching the face shield presents a combination which requires a willful act by the user of the helmet by way of rotation by the cam members in order to dissociate the face shield from its supporting frame. In addition and as will be described more fully herein, when the cam members are rotated to locked position, the face shield member is tensioned and drawn into close contact with the frame so as to substantially eliminate a gap therebetween. Where the protective helmet is used against airborne particulate matter this tightly sealed arrangement affords increased protection to the wearer.

The preferred embodiment of the present invention is illustrated in the accompanying drawings in which:

FIG. 1 is a side-elevational view of a conventional protective helmet and arcuate frame for mounting a face shield thereon and including a face shield of this invention attached thereto with the present rotatable cam members.

FIG. 2 is an enlarged segment in section in the region of the rotatable cam member taken along the line 2--2 of FIG. 1.

FIG. 3 is a segment in section with parts broken away of the mounting structure of FIG. 2 taken along the line 3--3.

FIG. 4 is a segment in section of the mounting structure of FIG. 2, taken along the line 4--4.

FIG. 5 is a plan view of a transparent face shield member suitable for attachment to a supporting frame utilizing the present cam members in cooperation therewith.

FIG. 6 is a side elevation of the region in which the face shield member, arcuate frame member, and locking cam member of this invention cooperate and illustrating the cam member in unlocked position with a portion of its tear drop handle broken away.

FIG. 7 is a view similar to that of FIG. 6 but showing the cam member and its handle rotated into position for locking the face shield to its arcuate frame.

More particularly with respect to the drawings, attention is directed to FIG. 1 which shows the overall relationship of the major components of the protective helmet and face shield. In the embodiment shown a protective helmet or hard hat 10 supports a conventional arcuate U-shaped channel 11. The visor portion 12 of hat 10 is inserted within channel 11. A coil spring 13 disposed between the two ends of channel 11 (one end not shown) maintains channel 11 in a fixed position on helmet 10. Arcuate frame 14 is pivotally mounted at each of its ends on channel 11. Frame 14 has a T-configuration (best seen in FIG. 2) including a top 15 and a leg 16. Face shield 17 is supported along its upper margin on the surface of leg 16 of arcuate T frame 14 as best seen in FIG. 1.

The cam member locking mechanism provided by this invention includes a rotatably mounted disc 18 having a thickness substantially equal or slightly greater than the thickness of face shield member 17. Disc 18 is eccentrically mounted on shaft 19. One end of shaft 19 is embedded within tear drop handle 20. The other end of shaft 19 includes head 21 to secure rotatable engagement with leg 16 of frame 14.

FIG. 5 illustrates the novel configuration of face shield member 17 useful in combination with the present locking structure. Generally, face shield member 17 has a substantially rectangular configuration and is suitably made from a clear plastic. Centrally along its upper margin 22 one or more apertures such as aperture 23 is provided for receiving studs such as stud 24 (see FIG. 1) therethrough. Studs such as stud 24 project from the contacting surface of leg 16 of arcuate frame 14. In the region of each end of top margin 22 of face shield 17 are slots 24 and 25 cooperatively shaped to receive tear drop handle 20. Slots 24 and 25 have a tear drop configuration to accommodate handle 20 but are slightly larger handle hancle 20 so as to readily slip on and off. The larger arcs of tear drop slots 24 and 25 are disposed closest to the side margins 26 and 27 respectively, of face shield 17.

In use, face shield 17 is disposed on leg 16 of arcuate frame 14 with the studs projecting from leg 15 such as stud 24 disposed through the cooperatively spaced apertures, such as aperture 23 in face shield 17. With handle 20 in the unlocked position (shown in FIG. 6) slot 25 is inserted thereover and the entire upper margin of face shield 17 is moved into contact with leg 16. A similar cam and handle structure is located on the other end of frame 14 (but is not shown) which receives and engages slot 24 on face shield 17. Handle 20 may then be rotated downwardly away from top 15 of frame 14 into locking position as shown in FIG. 7. During rotation of handle 20 the cam shoulder provided by eccentrically mounted disc 18 urges against the larger arc portion of tear drop slot 25. When in the locked position of FIG. 7, a substantial tension is created between the surface of disc 18 and the edges of slot 25 which together with the tension in the opposite direction developed at the other end of frame 14 in the same manner in connection with slot 24 holds the upper margin of face shield 17 in close conformity with the surface of leg 16. Face shield 17 may, of course, be readily removed by rotating handle 20 back to the unlocked position of FIG. 6.

FIGS. 2 and 3 particularly illustrates a safety feature of the present locking mechanism. Handle 20 is selected to be of a sufficient length so that during rotation the end of handle 20 abuts with the top 15 of T-shaped frame member 14. A complete rotation of handle 20 is thereby prevented. Consequently, when handle 20 is moved into locked position and turned upwardly into abuttment with top 15 inadvertent unlocking of face shield 17 is avoided. The top 15 of frame 14 prevents continuation of the rotation towards the unlocked position. At the same time movement away from the position of handle 20 in abuttment with frame top 15 requires the application of force for movement through the maximum tension position shown in FIG. 7. Therefore, handle 20 will remain in locked position until positively rotated by the wearer of the helmet.

Claims

What is claimed is:

1. Apparatus for mounting a face shield on a protective helmet comprising: a face shield having at least one elongate slot formed in the top margin thereof adjacent one end of said top margin, an arcuate frame having an angular cross-section including an extending top portion and a depending leg portion defining an arcuate surface for supporting said top margin of said face shield; means for attaching said frame to a protective helmet; means for attaching said face shield to said arcuate frame, including a cam shoulder portion, a handle portion, and means mounting said cam shoulder portion for rotation about an axis projecting from said depending leg portion of said arcuate frame, said handle portion mounted on said cam shoulder portion for rotation of said cam shoulder portion between first and second positions, so that when said face shield is positioned on said arcuate frame with said top margin supported on said arcuate surface of said depending portion and with said cam shoulder portion received in said elongate slot, said cam shoulder portion urges against the edge of said elongate slot to tension said face shield and hold it against said arcuate surface when said cam shoulder portion is in said second position and releases said tension when in said first position, said tension urging said handle against said top portion of said arcuate frame when said cam shoulder portion is in said second position tending to lock said cam shoulder portion in said second position to guard against inadvertent release.

2. Apparatus in accordance with claim 1 wherein said cam shoulder is an eccentrically mounted disc of a thickness substantially equal to the thickness of said face shield.

3. Apparatus in accordance with claim 2 wherein said handle portion comprises a tear drop shaped member extending radially from the top of said disc.

4. In combination, a T-shaped arcuate frame for mounting on a protective helmet having at least one stud extending outwardly from the leg of the T between the ends of the frame, a cam shoulder in the region of each end of the frame, means rotatably mounting said cam shoulder on each end of the leg of the T, a tear drop handle extending radially outwardly from the top of each cam shoulder, a face shield depending from the leg of said T frame having at least one aperture along its upper margin for receiving at least one stud, said face shield having a tear drop slot positioned to fit over each of said tear drop handles and with the larger arcs of the tear drop slots in contact with each of said cam shoulders whereby said handles may be rotated to tension said face shield into locked position on said T frame.

5. Apparatus for mounting a face shield on a protective helmet comprising: a face shield member having shaped slots formed in the top margin thereof adjacent the opposite ends of said top margin; an arcuate frame having a T configuration and having a depending leg providing a frame surface for contacting the top margin of the face shield member; means for attaching said frame to a protective helmet; face shield retainer means in the region of each end of said arcuate frame including a cam member rotatably mounted on each said end of said frame surface, said cam member comprising an eccentrically mounted disc of a thickness substantially equal to the thickness of said face shield; means connected for rotating said cam member comprising a tear drop shaped handle of a predetermined length extending radially from the top of said disc; said cam member extending above said frame surface to engage the shaped slot in the top margin of the face shield member whereby rotation of said cam member within said shaped slot against the edges thereof tensions said face shield member to said frame and wherein said predetermined handle length is sufficiently long so that during rotation the end of the tear drop abuts with the top of the T to prevent complete rotation.

6. A face shield in combination with a T-shaped frame for mounting the face shield to a protective helmet, said face shield being mounted on said T-shaped frame by means of fasteners extending from said T-shaped frame into slots at the ends of the upper margin of the face shield, said slots being tear drop shaped and positioned close to the upper edge of the face shield, said fasteners including a rotatable cam with a radially extending elongated handle secured thereto, said cam being received in said tear drop shaped slot for cooperation therewith, wherein the rotation of said handle to a position abutting the top of the T-shaped frame tensions said face shield with respect to said frame and simultaneously permits the tensioning of said face shield to hold the handle against the top of the frame to lock the rotatable cam in the face shield tensioning position.